实现增删改查

• namespace

namespace中的包名要和接口的包名一致

• select

  • id ：就是对应namespace中的方法名
  • resultType ：SQL语句的返回值
  • parameterType： 参数类型

编写接口

public interface UserDao {
    //获取全部用户
    List<User> getUserList();
    //根据id查询
    User getUserById(int id);
    //增加一个用户
    int addUser(User user);
    //修改用户
    int updateUser(User user);
    //删除一个用户
    int deleteUser(int id);
}

编写mapper中的sql

<mapper namespace="com.skl.dao.UserDao">
    <select id="getUserList" resultType="com.skl.pojo.User">
    select * from mybatis.user
  </select>
    <select id="getUserById" parameterType="int" resultType="com.skl.pojo.User">
        select * from mybatis.user where id= #{id}
    </select>
    <insert id="addUser" parameterType="com.skl.pojo.User">
        insert into mybatis.user (id,`name`,pwd) values (#{id},#{name},#{pwd})
    </insert>
    <update id="updateUser" parameterType="com.skl.pojo.User">
        update mybatis.user set pwd = #{pwd} where id = #{id}
    </update>
    <delete id="deleteUser" parameterType="com.skl.pojo.User">
        delete from mybatis.user where id = #{id}
    </delete>
</mapper>

测试

@Test
    public void test05(){
        SqlSession sqlSession = null;
        try {
            //获取sqlseaaion对象
            sqlSession = MybatisUtils.getSqlSession();
            //执行sql
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            int res = userDao.deleteUser(1010);
            if (res>0){
                System.out.println("delete success");
            }
            //提交事务
            sqlSession.commit();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            sqlSession.close();
        }
    }