day01 尚医通项目简介＋mybatisplus 入门

淡淡的烟草味﹌ 2023-10-13 14:33 21阅读 0赞

**目录**

内容介绍

尚医通项目介绍

业务流程

系统架构

MyBatisPlus简介

MyBatisPlus入门

MP配置日志输出

MP添加信息+主键策略

MP修改数据

MP实现自动填充

乐观锁

MP实现基本查询

MP实现删除数据

MP实现条件查询

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###### 内容介绍 ######

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   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;">1 尚医通项目介绍</p> <p style="margin-left:0;text-align:justify;">2业务流程</p> <p style="margin-left:0;text-align:justify;">3系统架构</p> <p style="margin-left:0;text-align:justify;">4 MyBatisPlus学习</p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
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###### 尚医通项目介绍 ######

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   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;">1</span></span><span style="background-color:#ffffff;"><span style="color:#000000;">、是什么、为什么</span></span></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;">尚医通即为网上预约挂号系统，网上预约挂号是近年来开展的一项便民就医服务，旨在缓解看病难、挂号难的就医难题，许多患者为看一次病要跑很多次医院，最终还不一定能保证看得上医生。网上预约挂号全面提供的预约挂号业务从根本上解决了这一就医难题。随时随地轻松挂号！不用排长队！</span></span></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
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###### 业务流程 ######

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   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><img alt="" height="841" src="https://img-blog.csdnimg.cn/0882930c7c354b54b239bd1eb3a58e1b.png" width="1189"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
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###### 系统架构 ######

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   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;">1</span></span><span style="background-color:#ffffff;"><span style="color:#000000;">、考虑因素</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;">性能、可扩展性、高可用、安全性、</span></span><strong><span style="background-color:#ffffff;"><span style="color:#222222;">成本</span></span></strong></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="982" src="https://img-blog.csdnimg.cn/9d647e1e3530471e88e5d59d22fe64e3.jpeg" width="1200"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
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###### MyBatisPlus简介 ######

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   <td style="border-color:#000000;vertical-align:top;width:414.8pt;"> <p style="margin-left:0;text-align:justify;">1、是什么</p> <p style="margin-left:0;text-align:justify;"><a href="https://github.com/baomidou/mybatis-plus" title="MyBatis-Plus" rel="nofollow">MyBatis-Plus</a><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（简称 MP）是一个</span></span>&nbsp;<a href="http://www.mybatis.org/mybatis-3/" title="MyBatis" rel="nofollow">MyBatis</a>&nbsp;<span style="background-color:#ffffff;"><span style="color:#2c3e50;">的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffff00;"><span style="color:#ff0000;">官网：</span></span><a href="http://mp.baomidou.com/" title="Redirect" rel="nofollow">Redirect</a></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、为什么</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">见课件</span></span></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
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###### MyBatisPlus入门 ######

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   <td style="border-color:#000000;vertical-align:top;width:414.8pt;"> <p style="margin-left:0;text-align:left;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、准备数据库表</span></span></span></p> <p style="margin-left:0;text-align:left;"><img alt="" height="127" src="https://img-blog.csdnimg.cn/99f79298b33445249c5ca88818a147c6.png" width="207"></p> <p style="margin-left:0;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#000000;">2</span><span style="color:#000000;">、创建工程</span></span></p> <p style="margin-left:0;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#000000;">（</span><span style="color:#000000;">1</span><span style="color:#000000;">）使用</span><span style="color:#000000;"> Spring Initializr </span><span style="color:#000000;">快速初始化一个</span><span style="color:#000000;"> Spring Boot </span><span style="color:#000000;">工程</span></span></p> <p style="margin-left:0;text-align:left;"><img alt="" height="633" src="https://img-blog.csdnimg.cn/586d336c6385401c9ff5f48da98d18bc.png" width="885"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）修改版本，添加依赖</span></span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="287" src="https://img-blog.csdnimg.cn/ac0224d370864c18903a85e0cac57637.png" width="914"></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#0e4a8e;">&lt;</span><span style="color:#0033b3;">dependencies</span><span style="color:#0e4a8e;">&gt;

&nbsp;&nbsp;&nbsp; </span><span style="color:#bcbf01;">&lt;</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#bc0ba2;">&lt;</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">org.springframework.boot</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">spring-boot-starter</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp; </span><span style="color:#bcbf01;">&lt;/</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#bc0ba2;">&lt;</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">org.springframework.boot</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">spring-boot-starter-test</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">scope</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">test</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">scope</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp; </span><span style="color:#bcbf01;">&lt;/</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp; </span><em><span style="color:#8c8c8c;">&lt;!--mybatis-plus--&gt;

&nbsp;&nbsp;&nbsp; </span></em><span style="color:#bcbf01;">&lt;</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#bc0ba2;">&lt;</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">com.baomidou</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">mybatis-plus-boot-starter</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">version</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">3.3.1</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">version</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp; </span><span style="color:#bcbf01;">&lt;/</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp; </span><em><span style="color:#8c8c8c;">&lt;!--mysql--&gt;

&nbsp;&nbsp;&nbsp; </span></em><span style="color:#bcbf01;">&lt;</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#bc0ba2;">&lt;</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">mysql</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">mysql-connector-java</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp; </span><span style="color:#bcbf01;">&lt;/</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp; </span><em><span style="color:#8c8c8c;">&lt;!--lombok</span></em><em><span style="color:#8c8c8c;">用来简化实体类</span></em><em><span style="color:#8c8c8c;">--&gt;

&nbsp;&nbsp;&nbsp; </span></em><span style="color:#bcbf01;">&lt;</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#bc0ba2;">&lt;</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">org.projectlombok</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">groupId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &lt;</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;</span><span style="color:#080808;">lombok</span><span style="color:#bc0ba2;">&lt;/</span><span style="color:#0033b3;">artifactId</span><span style="color:#bc0ba2;">&gt;

&nbsp;&nbsp;&nbsp; </span><span style="color:#bcbf01;">&lt;/</span><span style="color:#0033b3;">dependency</span><span style="color:#bcbf01;">&gt;

</span><span style="color:#0e4a8e;">&lt;/</span><span style="color:#0033b3;">dependencies</span><span style="color:#0e4a8e;">&gt;</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）添加配置信息</span></span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="168" src="https://img-blog.csdnimg.cn/759ba780e5444cf98bdf4d047c000c7e.png" width="325"></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><em><span style="color:#8c8c8c;"># </span></em><em><span style="color:#8c8c8c;">应用名称</span></em>
<em>
  </em><span style="color:#083080;">spring.application.name</span><span style="color:#080808;">=</span><span style="color:#067d17;">mybatisplus

</span><span style="color:#083080;">spring.datasource.driver-class-name</span><span style="color:#080808;">=</span><span style="color:#000000;">com</span><span style="color:#067d17;">.</span><span style="color:#000000;">mysql</span><span style="color:#067d17;">.</span><span style="color:#000000;">cj</span><span style="color:#067d17;">.</span><span style="color:#000000;">jdbc</span><span style="color:#067d17;">.</span><span style="color:#000000;">Driver

</span><span style="color:#083080;">spring.datasource.url</span><span style="color:#080808;">=</span><span style="color:#067d17;">jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8

</span><span style="color:#083080;">spring.datasource.username</span><span style="color:#080808;">=</span><span style="color:#067d17;">root

</span><span style="color:#083080;">spring.datasource.password</span><span style="color:#080808;">=</span><span style="color:#067d17;">123123</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、实现功能</span></span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）给启动类添加注解</span></span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="387" src="https://img-blog.csdnimg.cn/fe8487ad0d444d76bd3b169559d1830c.png" width="703"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）创建实体</span></span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#000000;">创建包&nbsp;</span></span><span style="background-color:#ffffff;"><span style="color:#ff0000;">entity&nbsp;</span></span><span style="background-color:#ffffff;"><span style="color:#000000;">编写实体类&nbsp;</span></span><code><span style="background-color:#ffffff;"><span style="color:#ff0000;">User.java</span></span></code></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="170" src="https://img-blog.csdnimg.cn/ffed79a5897e484ba1f6649b9f5d6b22.png" width="269"></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Data

</span><span style="color:#0033b3;">public class </span><span style="color:#000000;">User </span><span style="color:#3f9101;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">private </span><span style="color:#000000;">Long </span><span style="color:#871094;">id</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">private </span><span style="color:#000000;">String </span><span style="color:#871094;">name</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">private </span><span style="color:#000000;">Integer </span><span style="color:#871094;">age</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">private </span><span style="color:#000000;">String </span><span style="color:#871094;">email</span><span style="color:#080808;">;

</span><span style="color:#3f9101;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）创建</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">mapper</span></span></span></p> <pre style="margin-left:.0001pt;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Repository</span></span></pre> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#0033b3;">public interface </span><span style="color:#000000;">UserMapper </span><span style="color:#0033b3;">extends </span><span style="color:#000000;">BaseMapper</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">User</span><span style="color:#3f9101;">&gt; {

}</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">4</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）创建测试案例</span></span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="90" src="https://img-blog.csdnimg.cn/b179fb2608f54632a70389a8189acaa8.png" width="284"></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;">

<span style="color:#9e880d;">@Autowired

</span><span style="color:#0033b3;">private </span><span style="color:#000000;">UserMapper </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">;

</span><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">findAll</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">List</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">User</span><span style="color:#3f9101;">&gt; </span><span style="color:#000000;">users </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.selectList</span><span style="color:#3f9101;">(</span><span style="color:#0033b3;">null</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">users</span><span style="color:#080808;">.forEach</span><span style="color:#3f9101;">(</span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">::println</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
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###### MP配置日志输出 ######

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<em><span style="color:#8c8c8c;">#mybatis</span></em><em><span style="color:#8c8c8c;">日志</span></em>
<em>
  </em><span style="color:#083080;">mybatis-plus.configuration.log-impl</span><span style="color:#080808;">=</span><span style="color:#000000;">org</span><span style="color:#067d17;">.</span><span style="color:#000000;">apache</span><span style="color:#067d17;">.</span><span style="color:#000000;">ibatis</span><span style="color:#067d17;">.</span><span style="color:#000000;">logging</span><span style="color:#067d17;">.</span><span style="color:#000000;">stdout</span><span style="color:#067d17;">.</span><span style="color:#000000;">StdOutImpl</span></span></pre> <p style="margin-left:0;text-align:left;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
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###### MP添加信息+主键策略 ######

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   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、添加信息</span></span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">addUser</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">User user </span><span style="color:#080808;">= </span><span style="color:#0033b3;">new </span><span style="color:#080808;">User</span><span style="color:#3f9101;">()</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">user</span><span style="color:#080808;">.setName</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"zhang3"</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">user</span><span style="color:#080808;">.setAge</span><span style="color:#3f9101;">(</span><span style="color:#1750eb;">33</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">user</span><span style="color:#080808;">.setEmail</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"zhang3@qq.com"</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">int </span><span style="color:#000000;">insert </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.insert</span><span style="color:#3f9101;">(</span><span style="color:#000000;">user</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"insert = " </span><span style="color:#080808;">+ </span><span style="color:#000000;">insert</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><img alt="" height="179" src="https://img-blog.csdnimg.cn/18213a0ab1a54392a1d6170eb21d662c.png" width="944"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、主键策略</span></span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="314" src="https://img-blog.csdnimg.cn/ea28533277f44834b882731ef6084615.png" width="715"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
  </tr> 
 </tbody> 
</table>

###### MP修改数据 ######

<table> 
 <tbody> 
  <tr> 
   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">updateUser</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp; </span><span style="color:#000000;">User user </span><span style="color:#080808;">= </span><span style="color:#0033b3;">new </span><span style="color:#080808;">User</span><span style="color:#3f9101;">()</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">user</span><span style="color:#080808;">.setId</span><span style="color:#3f9101;">(</span><span style="color:#1750eb;">1677521904694546433L</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">user</span><span style="color:#080808;">.setName</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"zhang3upup"</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">int </span><span style="color:#000000;">update </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.updateById</span><span style="color:#3f9101;">(</span><span style="color:#000000;">user</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"update = " </span><span style="color:#080808;">+ </span><span style="color:#000000;">update</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
  </tr> 
 </tbody> 
</table>

###### MP实现自动填充 ######

<table> 
 <tbody> 
  <tr> 
   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、修改表增加两个字段</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;">在</span></span><span style="background-color:#ffffff;"><span style="color:#000000;">User</span></span><span style="background-color:#ffffff;"><span style="color:#000000;">表中添加</span></span><span style="background-color:#ffffff;"><span style="color:#000000;">datetime</span></span><span style="background-color:#ffffff;"><span style="color:#000000;">类型的新的字段</span></span><span style="background-color:#ffffff;"><span style="color:#ff0000;">&nbsp;create_time</span></span><span style="background-color:#ffffff;"><span style="color:#ff0000;">、</span></span><span style="background-color:#ffffff;"><span style="color:#ff0000;">update_time</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="40" src="https://img-blog.csdnimg.cn/75b29d5bfedf45f9829cce03e94edfa8.png" width="315"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、修改实体增加属性</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="293" src="https://img-blog.csdnimg.cn/d46ed73aee0c4d30b7e39c7d9ce34a6f.png" width="440"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、给实体的属性添加注解（什么时候填充）</span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@TableField</span><span style="color:#3f9101;">(</span><span style="color:#080808;">fill = </span><span style="color:#000000;">FieldFill</span><span style="color:#080808;">.</span><em><span style="color:#871094;">INSERT</span></em><span style="color:#3f9101;">)

</span><span style="color:#0033b3;">private </span><span style="color:#000000;">Date </span><span style="color:#871094;">createTime</span><span style="color:#080808;">;

</span><span style="color:#9e880d;">@TableField</span><span style="color:#3f9101;">(</span><span style="color:#080808;">fill = </span><span style="color:#000000;">FieldFill</span><span style="color:#080808;">.</span><em><span style="color:#871094;">INSERT_UPDATE</span></em><span style="color:#3f9101;">)

</span><span style="color:#0033b3;">private </span><span style="color:#000000;">Date </span><span style="color:#871094;">updateTime</span><span style="color:#080808;">;</span></span></pre> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">4</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、添加控制器（填充什么）</span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Component

</span><span style="color:#0033b3;">public class </span><span style="color:#000000;">MyMetaObjectHandler </span><span style="color:#0033b3;">implements </span><span style="color:#000000;">MetaObjectHandler </span><span style="color:#3f9101;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#9e880d;">@Override

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">insertFill</span><span style="color:#3f9101;">(</span><span style="color:#000000;">MetaObject </span><span style="color:#080808;">metaObject</span><span style="color:#3f9101;">) </span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">this</span><span style="color:#080808;">.setFieldValByName</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"createTime"</span><span style="color:#080808;">,</span><span style="color:#0033b3;">new </span><span style="color:#080808;">Date</span><span style="color:#0e4a8e;">()</span><span style="color:#080808;">,metaObject</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">this</span><span style="color:#080808;">.setFieldValByName</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"updateTime"</span><span style="color:#080808;">,</span><span style="color:#0033b3;">new </span><span style="color:#080808;">Date</span><span style="color:#0e4a8e;">()</span><span style="color:#080808;">,metaObject</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0e4a8e;">}

&nbsp;&nbsp;&nbsp; </span><span style="color:#9e880d;">@Override

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">updateFill</span><span style="color:#3f9101;">(</span><span style="color:#000000;">MetaObject </span><span style="color:#080808;">metaObject</span><span style="color:#3f9101;">) </span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">this</span><span style="color:#080808;">.setFieldValByName</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"updateTime"</span><span style="color:#080808;">,</span><span style="color:#0033b3;">new </span><span style="color:#080808;">Date</span><span style="color:#0e4a8e;">()</span><span style="color:#080808;">,metaObject</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0e4a8e;">}

</span><span style="color:#3f9101;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">5</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、测试</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">*</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">新增</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="91" src="https://img-blog.csdnimg.cn/1361a538fe994c51878d752c1740d759.png" width="1044"></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="91" src="https://img-blog.csdnimg.cn/22a36d2a126b41d697012fcdded9ab5d.png" width="895"></p> </td> 
  </tr> 
 </tbody> 
</table>

###### 乐观锁 ######

<table> 
 <tbody> 
  <tr> 
   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、乐观锁</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="502" src="https://img-blog.csdnimg.cn/3e20c7b71deb4e82aa568c0cc265f3e5.png" width="830"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、实现乐观锁</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）添加表字段、修改实体</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">ALTER TABLE `user` ADD COLUMN `version` INT</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="24" src="https://img-blog.csdnimg.cn/22e63ed94b314f09ac5d2aa9c5335023.png" width="334"></p> <pre style="margin-left:.0001pt;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#0033b3;">private </span><span style="color:#000000;">Integer </span><span style="color:#871094;">version</span><span style="color:#080808;">;</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）配置自动填充</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="65" src="https://img-blog.csdnimg.cn/8690cab5e54e4c9096519469dee00797.png" width="415"></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="240" src="https://img-blog.csdnimg.cn/a3bc7aa0a40e4e96876968fd3702b54f.png" width="816"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）给属性添加乐观锁注解</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="87" src="https://img-blog.csdnimg.cn/35036613941a43bd9a8e0dd84315114c.png" width="417"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">4</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）添加配置类，添加插件</span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@EnableTransactionManagement

@Configuration

@MapperScan</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"com.atguigu.mybatisplus.mapper"</span><span style="color:#3f9101;">)

</span><span style="color:#0033b3;">public class </span><span style="color:#000000;">MybatisPlusConfig </span><span style="color:#3f9101;">{

&nbsp;&nbsp;&nbsp; </span><em><span style="color:#8c8c8c;">/**

&nbsp;&nbsp;&nbsp;&nbsp; * </span></em><em><span style="color:#8c8c8c;">乐观锁插件</span></em>
<em><span style="color:#8c8c8c;">
&nbsp;&nbsp;&nbsp;&nbsp; */

&nbsp;&nbsp;&nbsp; </span></em><span style="color:#9e880d;">@Bean

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">public </span><span style="color:#000000;">OptimisticLockerInterceptor </span><span style="color:#00627a;">optimisticLockerInterceptor</span><span style="color:#3f9101;">() </span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">return new </span><span style="color:#080808;">OptimisticLockerInterceptor</span><span style="color:#3f9101;">()</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0e4a8e;">}

</span><span style="color:#3f9101;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">5</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">）测试</span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">updateUser</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp; </span><span style="color:#000000;">User user </span><span style="color:#080808;">=</span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.selectById</span><span style="color:#3f9101;">(</span><span style="color:#1750eb;">1677577776967778306L</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">user</span><span style="color:#080808;">.setName</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"wang5"</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">int </span><span style="color:#000000;">update </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.updateById</span><span style="color:#3f9101;">(</span><span style="color:#000000;">user</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"update = " </span><span style="color:#080808;">+ </span><span style="color:#000000;">update</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="90" src="https://img-blog.csdnimg.cn/a26e5c42cb6f4a39a61551d465333fba.png" width="1027"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
  </tr> 
 </tbody> 
</table>

###### MP实现基本查询 ######

<table> 
 <tbody> 
  <tr> 
   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、根据id查询数据</span></span></span></p> <pre style="margin-left:.0001pt;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;">User user </span><span style="color:#080808;">=</span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.selectById</span><span style="color:#3f9101;">(</span><span style="color:#1750eb;">1677577776967778306L</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、根据id集合查询数据</span></span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">getUserByIds</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">List</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">User</span><span style="color:#3f9101;">&gt; </span><span style="color:#000000;">users </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.selectBatchIds</span><span style="color:#3f9101;">(</span><span style="color:#000000;">Arrays</span><span style="color:#080808;">.<em>asList</em></span><span style="color:#0e4a8e;">(</span><span style="color:#1750eb;">1</span><span style="color:#080808;">, </span><span style="color:#1750eb;">2</span><span style="color:#080808;">, </span><span style="color:#1750eb;">3</span><span style="color:#0e4a8e;">)</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">users</span><span style="color:#080808;">.forEach</span><span style="color:#3f9101;">(</span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">::println</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><img alt="" height="83" src="https://img-blog.csdnimg.cn/fb5fb06925a64131b22f3669e9e45be6.png" width="948"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、根据多个条件查询</span></span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">getUserByInfo</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">Map</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">String</span><span style="color:#080808;">,</span><span style="color:#000000;">Object</span><span style="color:#3f9101;">&gt; </span><span style="color:#000000;">map </span><span style="color:#080808;">= </span><span style="color:#0033b3;">new </span><span style="color:#080808;">HashMap</span><span style="color:#3f9101;">&lt;&gt;()</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">map</span><span style="color:#080808;">.put</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"name"</span><span style="color:#080808;">, </span><span style="color:#067d17;">"zhang3upup"</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">map</span><span style="color:#080808;">.put</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"age"</span><span style="color:#080808;">, </span><span style="color:#1750eb;">33</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">List</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">User</span><span style="color:#3f9101;">&gt; </span><span style="color:#000000;">users </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.selectByMap</span><span style="color:#3f9101;">(</span><span style="color:#000000;">map</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">users</span><span style="color:#080808;">.forEach</span><span style="color:#3f9101;">(</span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">::println</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">4</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、分页查询</span></span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（1）添加分页插件</span></span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><em><span style="color:#8c8c8c;">/**

&nbsp;* </span></em><em><span style="color:#8c8c8c;">分页插件</span></em>
<em><span style="color:#8c8c8c;">
&nbsp;*/

</span></em><span style="color:#9e880d;">@Bean

</span><span style="color:#0033b3;">public </span><span style="color:#000000;">PaginationInterceptor </span><span style="color:#00627a;">paginationInterceptor</span><span style="color:#3f9101;">() </span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">return new </span><span style="color:#080808;">PaginationInterceptor</span><span style="color:#3f9101;">()</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（2）分页查询</span></span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">getUserByPage</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">Page</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">User</span><span style="color:#3f9101;">&gt; </span><span style="color:#000000;">page </span><span style="color:#080808;">= </span><span style="color:#0033b3;">new </span><span style="color:#080808;">Page</span><span style="color:#3f9101;">&lt;&gt;(</span><span style="color:#1750eb;">1</span><span style="color:#080808;">,</span><span style="color:#1750eb;">2</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><em><span style="color:#8c8c8c;">//</span></em><em><span style="color:#8c8c8c;">方式一</span></em>
<em><span style="color:#8c8c8c;">
//&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Page&lt;User&gt; userPage = userMapper.selectPage(page, null);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; //</span></em><em><span style="color:#8c8c8c;">方式二</span></em>
<em>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </em><span style="color:#871094;">userMapper</span><span style="color:#080808;">.selectPage</span><span style="color:#3f9101;">(</span><span style="color:#000000;">page</span><span style="color:#080808;">, </span><span style="color:#0033b3;">null</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">page</span><span style="color:#080808;">.getRecords</span><span style="color:#3f9101;">()</span><span style="color:#080808;">.forEach</span><span style="color:#3f9101;">(</span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">::println</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#000000;">page</span><span style="color:#080808;">.getCurrent</span><span style="color:#0e4a8e;">()</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#000000;">page</span><span style="color:#080808;">.getPages</span><span style="color:#0e4a8e;">()</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#000000;">page</span><span style="color:#080808;">.getSize</span><span style="color:#0e4a8e;">()</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#000000;">page</span><span style="color:#080808;">.getTotal</span><span style="color:#0e4a8e;">()</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#000000;">page</span><span style="color:#080808;">.hasNext</span><span style="color:#0e4a8e;">()</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#000000;">page</span><span style="color:#080808;">.hasPrevious</span><span style="color:#0e4a8e;">()</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
  </tr> 
 </tbody> 
</table>

###### MP实现删除数据 ######

<table> 
 <tbody> 
  <tr> 
   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、根据id删除</span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">delUserById</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">int </span><span style="color:#000000;">delete </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.deleteById</span><span style="color:#3f9101;">(</span><span style="color:#1750eb;">1677521904694546433L</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"delete = " </span><span style="color:#080808;">+ </span><span style="color:#000000;">delete</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><img alt="" height="91" src="https://img-blog.csdnimg.cn/2eaa545cfcba4edbacc743bc65f24dbf.png" width="350"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、根据ids批量删除</span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">delUserByIds</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#0033b3;">int </span><span style="color:#000000;">delete </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.deleteBatchIds</span><span style="color:#3f9101;">(</span><span style="color:#000000;">Arrays</span><span style="color:#080808;">.<em>asList</em></span><span style="color:#0e4a8e;">(

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#1750eb;">1677565142663000065L</span><span style="color:#080808;">,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span style="color:#1750eb;">1677577776967778306L

&nbsp;&nbsp;&nbsp; </span><span style="color:#0e4a8e;">)</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">.println</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"delete = " </span><span style="color:#080808;">+ </span><span style="color:#000000;">delete</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、逻辑删除</span></span></p> 
    <ul> 
     <li style="text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;"><span style="color:#ff0000;">物理删除：真实删除，</span>将对应数据从数据库中删除，之后查询不到此条被删除数据</span></span></li> 
     <li style="text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#000000;"><span style="color:#ff0000;">逻辑删除：假删除，</span>将对应数据中代表是否被删除字段状态修改为“被删除状态”，之后在数据库中仍旧能看到此条数据记录</span></span></li> 
    </ul><p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（1）修改表字段、实体添加属性</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">ALTER TABLE `user` ADD COLUMN `deleted` boolean</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="18" src="https://img-blog.csdnimg.cn/0c6c4aaa71cc4101b60e47cb81f616ed.png" width="322"></p> <pre style="margin-left:.0001pt;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#0033b3;">private </span><span style="color:#000000;">Integer </span><span style="color:#871094;">deleted</span><span style="color:#080808;">;</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（2）实现自动填充</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="52" src="https://img-blog.csdnimg.cn/96b02ca0e5e742888912e5efd9be5532.png" width="423"></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="193" src="https://img-blog.csdnimg.cn/da24f8268c8c4f82bd4ae16f289edd55.png" width="822"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（3）添加注解标注逻辑删除</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="97" src="https://img-blog.csdnimg.cn/d800ba73cb6343dda4a02992b9b01b49.png" width="448"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（4）添加配置（符合如下默认规则，可以不加配置）</span></span></p> <pre style="margin-left:.0001pt;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#083080;">mybatis-plus.global-config.db-config.logic-delete-value</span><span style="color:#080808;">=</span><span style="color:#067d17;">1

</span><span style="color:#083080;">mybatis-plus.global-config.db-config.logic-not-delete-value</span><span style="color:#080808;">=</span><span style="color:#067d17;">0</span></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">（5）测试</span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">*</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">删除</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="89" src="https://img-blog.csdnimg.cn/1b7165f4b9cb490099a48a5b8dbd7b74.png" width="585"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">*</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">查询</span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="41" src="https://img-blog.csdnimg.cn/54050eb9255c4b0b847813ddbdbcebf4.png" width="921"></p> <p style="margin-left:0;text-align:justify;"></p> </td> 
  </tr> 
 </tbody> 
</table>

###### MP实现条件查询 ######

<table> 
 <tbody> 
  <tr> 
   <td style="border-color:#000000;vertical-align:top;width:426.1pt;"> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">1</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、wrapper</span></span></span></p> <p style="margin-left:0;text-align:justify;"><img alt="" height="332" src="https://img-blog.csdnimg.cn/964a2870c51a4de88f6a5f497342e519.png" width="801"></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">条件查询构造器</span></span></span></p> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">2</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、常用方法</span></span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><em><span style="color:#8c8c8c;">//1 eq</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">ne

//2ge</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">gt</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">le</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">lt

//3between

//4like

//5orderByDesc

//6select</span></em></span></pre> <p style="margin-left:0;text-align:justify;"><span style="background-color:#ffffff;"><span style="background-color:#ffffff;"><span style="color:#2c3e50;">3</span></span><span style="background-color:#ffffff;"><span style="color:#2c3e50;">、测试</span></span></span></p> <pre style="margin-left:.0001pt;text-align:left;"><span style="background-color:#ffffff;"><span style="color:#9e880d;">@Test

</span><span style="color:#0033b3;">public void </span><span style="color:#00627a;">getUserByWrapper</span><span style="color:#3f9101;">()</span><span style="color:#0e4a8e;">{

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">QueryWrapper</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">User</span><span style="color:#3f9101;">&gt; </span><span style="color:#000000;">wrapper </span><span style="color:#080808;">= </span><span style="color:#0033b3;">new </span><span style="color:#080808;">QueryWrapper</span><span style="color:#3f9101;">&lt;&gt;()</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><em><span style="color:#8c8c8c;">//1 eq</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">ne

&nbsp;&nbsp;&nbsp; //wrapper.eq("name","zhang3");

&nbsp;&nbsp;&nbsp; //2ge</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">gt</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">le</span></em><em><span style="color:#8c8c8c;">、</span></em><em><span style="color:#8c8c8c;">lt

&nbsp;&nbsp;&nbsp; //wrapper.ge("age",33);

&nbsp;&nbsp;&nbsp; //3between

&nbsp;&nbsp;&nbsp; //wrapper.between("age",33,55);

&nbsp;&nbsp;&nbsp; //4like

&nbsp;&nbsp;&nbsp; //wrapper.like("name","J");

&nbsp;&nbsp;&nbsp; //5orderByDesc

&nbsp;&nbsp;&nbsp; </span></em><span style="color:#000000;">wrapper</span><span style="color:#080808;">.orderByDesc</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"age"</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><em><span style="color:#8c8c8c;">//6select

&nbsp;&nbsp;&nbsp; </span></em><span style="color:#000000;">wrapper</span><span style="color:#080808;">.select</span><span style="color:#3f9101;">(</span><span style="color:#067d17;">"name"</span><span style="color:#080808;">,</span><span style="color:#067d17;">"age"</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">List</span><span style="color:#3f9101;">&lt;</span><span style="color:#000000;">User</span><span style="color:#3f9101;">&gt; </span><span style="color:#000000;">users </span><span style="color:#080808;">= </span><span style="color:#871094;">userMapper</span><span style="color:#080808;">.selectList</span><span style="color:#3f9101;">(</span><span style="color:#000000;">wrapper</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

&nbsp;&nbsp;&nbsp; </span><span style="color:#000000;">users</span><span style="color:#080808;">.forEach</span><span style="color:#3f9101;">(</span><span style="color:#000000;">System</span><span style="color:#080808;">.</span><em><span style="color:#871094;">out</span></em><span style="color:#080808;">::println</span><span style="color:#3f9101;">)</span><span style="color:#080808;">;

</span><span style="color:#0e4a8e;">}</span></span></pre> <p style="margin-left:0;text-align:justify;"></p> </td> 
  </tr> 
 </tbody> 
</table>

######  ######

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