Mapper代理文件实现

Mapper代理的开发方式，程序员只需要编写mapper接口（相当于dao接口）即可。Mybatis会自动的为mapper接口生成动态代理实现类。

规范

不需编写Dao文件 使用Mapper代理

编写数据操作接口

package edu.ccit.cn.domain;

/**
 * @program: mybatis02_mapper
 * @description
 * @author: LIANG
 * @create: 2021-05-30 14:50
 **/
public class User {
    private int id;
    private String username;
    private String password;

    public User() {
    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public int getId() {
        return id;
    }

    public void setId(int 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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

编写Mapper接口

package edu.ccit.cn.mapper;

import edu.ccit.cn.domain.User;

/**
 * @program: mybatis02_mapper
 * @description
 * @author: LIANG
 * @create: 2021-05-30 14:52
 **/
public interface UserMapper {
    public void save(User user);
    public User findUserById(int id);
}

编写映射文件

<?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">
<!--
    namespace：命名空间，它的作用就是对SQL进行分类化管理，可以理解为SQL隔离
    注意：使用mapper代理开发时，namespace有特殊且重要的作用
 -->
<mapper namespace="edu.ccit.cn.mapper.UserMapper">
    <select id="findUserById" parameterType="int" resultType="edu.ccit.cn.domain.User">
        select * from t_user where id=#{?}
    </select>
    <insert id="save" parameterType="edu.ccit.cn.domain.User">
        insert into t_user (username,password)values (#{username},#{password})
    </insert>
</mapper>

将映射文件配置到全局配置文件中

<?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>
    <!-- 配置mybatis的环境信息 -->
    <environments default="development">
        <environment id="development">
            <!-- 配置JDBC事务控制，由mybatis进行管理 -->
            <!--配置数据源-->
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybites?serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="sqlmap/UserMapper.xml"></mapper>
    </mappers>
</configuration>

测试

import edu.ccit.cn.domain.User;
import edu.ccit.cn.mapper.UserMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;

/**
 * @program: mybatis02_mapper
 * @description
 * @author: LIANG
 * @create: 2021-05-30 15:02
 **/
public class Test01_mapper {
    SqlSessionFactory ssf;
    @Before
    public void setup() throws IOException {
        //读取配置文件
        InputStream is = Resources.getResourceAsStream("sqlMapConfig.xml");
        //加载会话工厂
        ssf = new SqlSessionFactoryBuilder().build(is);
    }
    @Test
    public void method01(){
        SqlSession session = ssf.openSession();
        //通过session获取代理（jdk实现的代理）
        UserMapper userMapper = session.getMapper(UserMapper.class);
        //添加用户
        User user = new User();
        user.setUsername("孙兰香");
        user.setPassword("wuzhongping");
        userMapper.save(user);
        session.commit();

    }

}