Mybatis增删改查

1. 编写映射文件UserMapper.xml

<?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="userMapper">
    <!--namespace : 命名空间：与id属性共同构成唯一标识 namespace.id: user.findAll
        resultType: 返回结果类型（自动映射封装）：要封装的实体的全路径
    -->

    <!-- 查询所有 -->
    <select id="findAll" resultType="uSeR">
        select * from user
    </select>

    <!--新增用户-->
    <!--#{} : mybatis中的占位符，等同于JDBC中的？
        parameterType ：指定接收到的参数类型 -->
    <insert id="saveUser" parameterType="user">
        insert into user(username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})
    </insert>


    <!--更新用户-->
    <update id="updateUser" parameterType="user">
        update user set username = #{username},birthday = #{birthday},sex = #{sex},address = #{address} where id = #{id}
    </update>


    <!--删除用户 java.lang.Integer-->
    <delete id="deleteUser" parameterType="int">
        delete from user where id = #{abc}
    </delete>



</mapper>

2）编写测试类

package com.lagou.test;

import com.lagou.domain.User;
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.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;

public class MybatisTest {

    /*
        测试新增用户
     */
    @Test
    public void testSave() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);


        User user = new User();
        user.setUsername("自动提交事务");
        user.setBirthday(new Date());
        user.setSex("男");
        user.setAddress("北京海淀");

        sqlSession.insert("userMapper.saveUser",user);

        // 手动提交事务
        //sqlSession.commit();
        sqlSession.close();

    }



    /*
    测试更新用户
 */
    @Test
    public void testUpdate() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();


        User user = new User();
        user.setId(4);
        user.setUsername("lucy");
        user.setBirthday(new Date());
        user.setSex("女");
        user.setAddress("北京朝阳");

        sqlSession.update("userMapper.updateUser",user);

        // 手动提交事务
        sqlSession.commit();
        sqlSession.close();

    }



    /*
    测试删除用户
    */
    @Test
    public void testDelete() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();

       sqlSession.delete("userMapper.deleteUser",4);

        // 手动提交事务
        sqlSession.commit();
        sqlSession.close();

    }




}

3. 新增注意事项

4. 修改注意事项

5. 删除注意事项

6.知识小结

节选自拉钩教育JAVA系列培训课程