mybatis CURD

Mybatis CURD

1、目录结构

2、select

mapper.xml

<select id="selectUserById" resultType="entity.User">
    select * from user where id=#{id}
</select>

接口：

User selectUserById(int id);

3、insert

mapper.xml：

<insert id="addUser" parameterType="entity.User">
        insert
        into user (id,name,pwd)
        values (#{id},#{name},#{pwd})
</insert>

接口：

int addUser(User user);

4、delete

mapper.xml:

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

接口：

int deleteUser(int id);

5、update

mapper.xml:

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

接口：

int updateUser(User user);

6、Test类

    @Test
    public void selectUserById() {
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        System.out.println(mapper.selectUserById(1));
        session.close();
        }

    @Test
    public void insertUser() {
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        mapper.addUser(new User(4, "no4", "23333"));
        session.commit();
        session.close();
    }

    @Test
    public void deleteUser() {
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        mapper.deleteUser(4);
        session.commit();
        session.close();
    }

    
    @Test
    public void updateUser() {
        SqlSession session = MybatisUtils.getSession();
        UserMapper mapper = session.getMapper(UserMapper.class);
        mapper.updateUser(new User(1, "陈修行_new", "5555"));
        session.commit();
        session.close();
    }

7、注意点

1.增删改需要提交事物，务必调用SqlSession的commit方法。
2.parameterType属性为参数的类型，同样是全限定名，同时在sql语句中#{}可以直接取出

8、总结

对数据库的操作越来越简单了，只需要添加接口方法，然后再把对应的mapper中的sql语句补全就OK了，增删改查都大同小异，注意好对应关系就可以