Mybatis框架快速入门

落日映苍穹つ 2021-12-11 22:41 452阅读 0赞

# 一、场景模拟 #

基于自定义Mybatis框架和已有的Mysql数据库Mybatis，查询所有用户信息。

# 二、创建工程并引入Mybatis框架的坐标 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzM5MTc5OTkz_size_16_color_FFFFFF_t_70]

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.william</groupId>
        <artifactId>TestFormalMybatisFramework</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <properties>
            <maven.compiler.source>1.8</maven.compiler.source>
            <maven.compiler.target>1.8</maven.compiler.target>
        </properties>
        <dependencies>
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.4.5</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.6</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
        </dependencies>
    </project>

# 三、创建domain #

package com.william.domain;
    
    import Framework.domain.Mapper;
    
    import java.util.HashMap;
    import java.util.Map;
    
    /**
     * @author ：lijunxuan
     * @date ：Created in 2019/7/9  16:54
     * @description ：
     * @version: 1.0
     */
    public class User {
        private Integer id;
        private String username;
        private String password;
        private String sex;
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", username='" + username + '\'' +
                    ", password='" + password + '\'' +
                    ", sex='" + sex + '\'' +
                    '}';
        }
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getUsername() {
            return username;
        }
    
        public void setUsername(String username) {
            this.username = username;
        }
    
        public String getPassword() {
            return password;
        }
    
        public void setPassword(String password) {
            this.password = password;
        }
    
        public String getSex() {
            return sex;
        }
    
        public void setSex(String sex) {
            this.sex = sex;
        }
    }

# 四、创建Sql文件UserMapper.xml #

加入mybatis的约束

<?xml version="1.0" encoding="utf-8" ?>
    <!DOCTYPE mapper
            PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.william.dao.UserDao">
        <select id="findAll" resultType="com.william.domain.User">
            select * from user
        </select>
    </mapper>

# 五、3.1.5 创建核心配置文件SqlMapConfig.xml #

## 加入mybatis的约束，不加会报错 ##

报错Cause: org.xml.sax.SAXParseException lineNumber: 2; columnNumber: 16; 文档根元素 "

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE configuration
            PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        <environments default="development">
            <environment id="development">
                <transactionManager type="JDBC" />
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.jdbc.Driver" />
                    <property name="url" value="jdbc:mysql://127.0.0.1:3306/web02?characterEncoding=utf8" />
                    <property name="username" value="root" />
                    <property name="password" value="root" />
                </dataSource>
            </environment>
        </environments>
    	<mappers>
    		<mapper resource="com/william/mapper/UserMapper.xml"></mapper>
        </mappers>
    </configuration>

# 六、3.1.6 测试 #

## 1.测试程序 ##

package com.william;
    
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.junit.Test;
    import java.io.InputStream;
    import java.util.List;
    
    /**
     * @author ：lijunxuan
     * @date ：Created in 2019/7/9  17:05
     * @description ：
     * @version: 1.0
     */
    public class TestFramework {
        @Test
        public void  test(){
            //获取核心配置文件的流对象
            InputStream inputStream = TestFramework.class.getClassLoader().getResourceAsStream("SqlMapConfig.xml");
            //构建sqlSessionFactory对象
           SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
           //生产SqlSession对象
            SqlSession sqlSession = sqlSessionFactory.openSession();
            //调用selectList方法
            List list = sqlSession.selectList("com.william.dao.UserDao" + "." + "findAll");
            for (Object o : list) {
                System.out.println(o);
            }
            //释放资源
            sqlSession.close();
        }
    }

## 2.测试效果 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzM5MTc5OTkz_size_16_color_FFFFFF_t_70 1]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzM5MTc5OTkz_size_16_color_FFFFFF_t_70]: /images/20211211/17c5412f3bc44b378cf303a0b963b51e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzM5MTc5OTkz_size_16_color_FFFFFF_t_70 1]: /images/20211211/5fdf02dc8449481a81239af28b1dc4fe.png