Mybatis系列--02-Mybatis实现增删改查

Mybatis实现增删改查

概述

本文主要讲述利用 Mybatis实现增删改查，详细的环境等配置详见https://www.cnblogs.com/Oh-mydream/p/16468030.html
文本仅修改核心内容，对工具类等不再做详细的展开

注意点

数据库的增删改操作需要提交事务

实践

UserDao.java

package com.kuang.dao;

import java.util.List;

import com.kuang.pojo.User;

/**
 * 功能描述
 *
 * @since 2022-07-11
 */
public interface UserDao {
    List<User> getUserList();

    int addUser(User user);

    int updateUser(User user);

    User getUser(int id);

    int deleteUser(int id);

}

UserMapper.xml的配置文件

<?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">
<mapper namespace="com.kuang.dao.UserDao">
    <select id="getUserList" resultType="com.kuang.pojo.User">
        select *
        from user
    </select>

    <insert id="addUser" parameterType="com.kuang.pojo.User">
        insert into user (`id`, `name`, `pwd`)
        values (#{id}, #{name}, #{pwd})
    </insert>
    <select id="getUser" parameterType="int" resultType="com.kuang.pojo.User">
        select *
        from user
        where id = #{id}
    </select>

    <delete id="deleteUser" parameterType="int">
        delete
        from user
        where id = #{id}
    </delete>
    <update id="updateUser" parameterType="com.kuang.pojo.User">
        update user
        set name =#{name},
            pwd=#{pwd}
        where id = #{id}
    </update>
</mapper>

测试类

package com.kuang.dao;

import java.util.Iterator;
import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.kuang.pojo.User;
import com.kuang.util.MyBatisUtils;

/**
 * 功能描述
 *
 * @since 2022-07-11
 */
public class UserDaoTest {
    @Test
    public void test1() {
        SqlSession sqlSession = MyBatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        List<User> userList = mapper.getUserList();
        Iterator<User> iterator = userList.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }

    }

    @Test
    public void get() {
        SqlSession sqlSession = MyBatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        User user = mapper.getUser(1);
        System.out.println(user);
    }

    @Test
    public void add() {
        SqlSession sqlSession = MyBatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        int result = mapper.addUser(new User(4, "lili", "123"));
        // 增删改操作需要提交事务 否则不生效
        sqlSession.commit();
    }

    @Test
    public void update() {
        SqlSession sqlSession = MyBatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        int result = mapper.updateUser(new User(4, "lil2", "333"));
        sqlSession.commit();
    }

    @Test
    public void delete() {
        SqlSession sqlSession = MyBatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        int result = mapper.deleteUser(4);
        sqlSession.commit();
    }

}