MyBatis的增删改查实现

首先还是使用上一篇文章相同的数据表和实体类，如下图所示

 

 

package com.loubin.pojo;

public class User {
    private int id;
    private String name;
    private String pwd;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

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

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }
}

 

 

然后是在接口UserMapper.java中增加增删改查的接口，如下代码所示

package com.loubin.dao;

import com.loubin.pojo.User;

import java.util.List;

public interface UserMapper {
    List<User> getUserList();
    User getUserById(int id);
    int insertUser(User user);
    int updateUser(User user);
    int deleteUser(int id);
}

 

然后在映射文件UserMapper.xml中增加sql实现，如下代码所示

<?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.loubin.dao.UserMapper">
    <select id="getUserList" resultType="com.loubin.pojo.User">
        select * from mybatis.user;
    </select>

    <select id="getUserById" resultType="com.loubin.pojo.User" parameterType="int">
        select * from user where id = #{id};
    </select>

    <insert id="insertUser" parameterType="com.loubin.pojo.User">
        insert into user(id, name, pwd) values (#{id}, #{name}, #{pwd});
    </insert>

    <update id="updateUser" parameterType="com.loubin.pojo.User">
        update user set  name = #{name}, pwd=#{pwd} where id = #{id};
    </update>

    <delete id="deleteUser" parameterType="int">
        delete
        from user
        where id = #{id};
    </delete>
</mapper>

 

然后是在测试类中进行测试，如下代码所示，别忘了在插入，修改，删除的方法中要显示提交，即session.commit()

package com.loubin.dao;

import com.loubin.pojo.User;
import com.loubin.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserMapperTest {
    @Test
    public void test(){
        SqlSession session = MybatisUtils.getSqlSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> userList = userMapper.getUserList();

        for (User user : userList) {
            System.out.println(user);
            System.out.println("lll");
        }
        session.close();
    }

    @Test
    public void selectUserById() {
        SqlSession session= MybatisUtils.getSqlSession();
        UserMapper userMapper= session.getMapper(UserMapper.class);
        User user = userMapper.getUserById(1);
        System.out.println(user);
        session.close();
    }

    @Test
    public void insertUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper= sqlSession.getMapper(UserMapper.class);
        userMapper.insertUser(new User(6, "哈哈", "22222"));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void updateUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        userMapper.updateUser(new User(6, "嘿嘿", "33333"));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void deleteUser(){
        SqlSession session = MybatisUtils.getSqlSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        userMapper.deleteUser(6);
        session.commit();
        session.close();
    }
}