ResultMap结果集映射

ResultMap结果集映射，可以解决数据库中的表字段名与实体类中的属性名不同的问题

//实体类
public class User {
    int userId;
    String userName;
    String userPwd;
    public User() {}
    public User(int userId, String userName, String userPwd) {
        this.userId = userId;
        this.userName = userName;
        this.userPwd = userPwd;
    }
    public int getUserId() {
        return userId;
    }
    public void setUserId(int userId) {
        this.userId = userId;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getUserPwd() {
        return userPwd;
    }
    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }
    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userPwd='" + userPwd + '\'' +
                '}';
    }
}

<?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=绑定一个对应的Dao/Mapper接口 -->
<!-- 等同于JDBC中的UserDaoImpl(接口实现类)，转变为Mapper配置文件 -->
<mapper namespace="com.comprehensive.dao.UserMapper">
    <!-- resultMap结果集 解决属性名和字段名不一致的问题 -->
    <resultMap id="map1" type="com.comprehensive.pojo.User">
        <result column="id" property="userId"></result>
        <result column="name" property="userName"></result>
        <result column="pwd" property="userPwd"></result>
    </resultMap>
    <select id="getListOfUser" resultMap="map1" resultType="com.comprehensive.pojo.User">
        select * from mybatis.user
    </select>
</mapper>

//测试类
public class UserMapper_Test {
    @Test
    //resultMap结果集 解决属性名和字段名不一致的问题
    public void test() {
        SqlSession sqlSession = MyBatis_Util.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        for(User user : mapper.getListOfUser()) System.out.println(user);
        sqlSession.close();
    }
}