MyBatis-6-MyBatis的逆向工程（MBG）

朱雀 2023-10-05 09:11 9阅读 0赞

**目录**

1：正向工程和逆向工程

2：导包

3：写配置（放在项目根目录下，这样好找）

4：运行代码生成

5：测试

6：复杂查询

1：查询全部

2：利用id排序

3：去重的

4：name模糊查询

5：连个查询条件用or链接

6：总结Criteria

--------------------

# 1：正向工程和逆向工程 #

正向：

先建表table----再写javaBean---写BookDao---dao.xml---xxx

逆向工程：

根据数据表table，逆向分析数据表，自动生成javaBean---BookDao---dao.xml---xxx

MBG：MyBatis Generator：代码生成器；

MyBatis官方提供的代码生成器；帮我们逆向生成javabean和dao以及mapper.xml等；

# 2：导包 #

<dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.4</version>
            </dependency>
    
            
            
            <dependency>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-core</artifactId>
                <version>1.4.0</version>
            </dependency>
    
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.20</version>
            </dependency>
            
            
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>1.2.17</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.13</version>
            </dependency>

# 3：写配置（放在项目根目录下，这样好找） #

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE generatorConfiguration
            PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
            "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
    
    <generatorConfiguration>
    
        
        <context id="DB2Tables" targetRuntime="MyBatis3">
            <commentGenerator>
                <property name="suppressAllComments" value="true"/>
            </commentGenerator>
            
            <jdbcConnection
    
                    driverClass="com.mysql.cj.jdbc.Driver"
                    connectionURL="jdbc:mysql://127.0.0.1:3306/mybatis?useSSL=false&serverTimezone=Hongkong&characterEncoding=utf-8&autoReconnect=true"
    
                    userId="root"
    
                    password="123456">
            </jdbcConnection>
    
            <javaTypeResolver>
                <property name="forceBigDecimals" value="false" />
            </javaTypeResolver>
    
            
            <javaModelGenerator targetPackage="com.wkl.bean"
                                targetProject=".\src\main\java">
                <property name="enableSubPackages" value="true" />
                <property name="trimStrings" value="true" />
            </javaModelGenerator>
    
            
            <sqlMapGenerator targetPackage="com.wkl.dao"
                             targetProject=".\src\main\resources">
                <property name="enableSubPackages" value="true" />
            </sqlMapGenerator>
    
            
            <javaClientGenerator type="XMLMAPPER"
                                 targetPackage="com.wkl.dao"
    
                                 targetProject=".\src\main\java">
                <property name="enableSubPackages" value="true" />
            </javaClientGenerator>
    
            
            <table tableName="t_employee" domainObjectName="Employee"></table>
    
        </context>
    </generatorConfiguration>

# 4：运行代码生成 #

import org.mybatis.generator.api.MyBatisGenerator;
    import org.mybatis.generator.config.Configuration;
    import org.mybatis.generator.config.xml.ConfigurationParser;
    import org.mybatis.generator.exception.InvalidConfigurationException;
    import org.mybatis.generator.exception.XMLParserException;
    import org.mybatis.generator.internal.DefaultShellCallback;
    
    import java.io.File;
    import java.io.IOException;
    import java.sql.SQLException;
    import java.util.ArrayList;
    import java.util.List;
    
    /**
     * Description:
     * Date:       2020/8/27 - 上午 11:36
     * author:     wangkanglu
     * version:    V1.0
     */
    public class TestMGB {
        public static void main(String[] args) throws IOException, XMLParserException, InvalidConfigurationException, SQLException, InterruptedException {
            List<String> warnings = new ArrayList<String>();
            boolean overwrite = true;
            File configFile = new File("MGB.xml");
            ConfigurationParser cp = new ConfigurationParser(warnings);
            Configuration config = cp.parseConfiguration(configFile);
            DefaultShellCallback callback = new DefaultShellCallback(overwrite);
            MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,
                    callback, warnings);
            //代码生成
            myBatisGenerator.generate(null);
            System.out.println("生成ok了！");
        }
    }

# 5：测试 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxNjk0OTA2_size_16_color_FFFFFF_t_70][]

# 6：复杂查询 #

## 1：查询全部 ##

## ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxNjk0OTA2_size_16_color_FFFFFF_t_70 1][] 2：利用id排序 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxNjk0OTA2_size_16_color_FFFFFF_t_70 2][]

## 3：去重的 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxNjk0OTA2_size_16_color_FFFFFF_t_70 3][]

## 4：name模糊查询 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxNjk0OTA2_size_16_color_FFFFFF_t_70 4][]

## 5：连个查询条件用or链接 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQxNjk0OTA2_size_16_color_FFFFFF_t_70 5][]

## 6：总结Criteria ##

通俗来说；每一个Criteria都可以对该表所有的属性做出条件限制；

每一个Criteria之间还可以用or链接；

每一个Criteria里面都对表中所有属性做出了条件限制；比如idnotin();namelike();等等，需要用的时候根据方法名直译即可；

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