有部分相同不需要修改可以点击--->简单的Mybatis项目

 

 

1.配置Maven依赖

2.配置环境文件mybatis-config.xml

3.编写MybatisUtils工具类

4.编写实体类User

5.实体类UserMapperr的接口  （在小进阶后  实体类名字修改为了UserMapper）

package com.zxy.dao;

import com.zxy.pojo.User;

import java.util.List;

public interface UserMapper {
    //获取全部用户
    List<User> getUserList();

    //根据ID查询用户
    User getUserById(int id);

    //insert一个用户
    int addUser(User user);

    //修改用户
    int updateUser(User user);

    //删除一个用户
    int deleteUser(int id);
}

6.编写基于 XML的对于sql的映射语句UserMapper.xml(在dao目录下创建)

 增删改不需要返回结果类型

注意！！  有部分人的xml里面可能不能写注释  可以尝试将XML文件顶部的encoding="UTF-8"   改为  “UTF8”

 

<?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.zxy.dao.UserMapper">
    <select id="getUserList" resultType="com.zxy.pojo.User" >
        select * from mybatis.user;
    </select>
　　　//查询
    <select id="getUserById" parameterType="int" resultType="com.zxy.pojo.User">
        select * from mybatis.user where id = #{id};
    </select>
　　//增加
    <insert id="addUser" parameterType="com.zxy.pojo.User">
        insert into mybatis.user(id, name, pwd) VALUES (#{id},#{name},#{pwd})
    </insert>
　　//修改
    <update id="updateUser" parameterType="com.zxy.pojo.User">
        update mybatis.user set name =#{name},pwd=#{pwd}  where id = #{id};
    </update>
　　//删除
    <delete id="deleteUser" parameterType="int">
        delete from mybatis.user
                 where id = #{id};
    </delete>
</mapper>

 

7.编写测试类

注意！！！：增删改是需要提交事务  ！！！

有两种方法 1.如下面所示        手动提交 sqlSession.commit();

　　　　　　　2.在工具类MybatisUtils中        

return sqlSessionFactory.openSession(true); 

在括号中传值true  可以设置为自动提交

 

 

1.查询

 public void test(){

            //1.获取sqlSession对象
            SqlSession sqlSession = MybatisUtils.getSqlSession();
            //2.
            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
            List<User> userList = userMapper.getUserList();
            for ( User user :userList) {
                System.out.println(user);
            }

            //关闭SqlSession
            sqlSession.close();
        }

        @Test
        public void test2(){
            SqlSession sqlSession = MybatisUtils.getSqlSession();
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            User user = mapper.getUserById(1);
            System.out.println(user);
            sqlSession.close();
        }

 

2.增加

@Test
        public void test3(){
            SqlSession sqlSession = MybatisUtils.getSqlSession();
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            int rs = mapper.addUser(new User(4,"爱德华","44451313"));
            if(rs>0){
                System.out.println("插入成功");
            }
            //提价事务
            sqlSession.commit();
            sqlSession.close();
    }

 

3.修改

 @Test
            public void test4() {
                SqlSession sqlSession = MybatisUtils.getSqlSession();
                UserMapper mapper = sqlSession.getMapper(Use