Mybatis入门之CRUD mybatis

xml元素

namespace
xml中的namespace与dao接口的包名一致
id
xml中的id与dao接口的方法名一致
resultType
sql语句执行的返回值
parameterType
参数类型

select

编写接口

//查询全部用户 List getUserList();

编写sql语句

select * from mybatis.user

测试

@Test public void test(){ //获得SqlSession对象 SqlSession sqlSession = MybatisUtils.getSqlSession(); //方式一：执行SQL推荐 UserMapper userMapper = sqlSession.getMapper(UserMapper.class); List userList = userMapper.getUserList(); //方式二： //List userList = sqlSession.selectList("com.sunfl.dao.UserDao.getUserList"); for (User user : userList) { System.out.println(user); }//关闭sqlSession sqlSession.close(); }

insert

编写接口

//新增一个用户 int addUser(User user);

编写sql语句

insert into mybatis.user (id, name, pwd) values (#{id},#{name},#{pwd});

测试

@Test public void addUser(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); mapper.addUser(new User(4, "哈哈哈", "12323")); sqlSession.commit(); sqlSession.close(); }

update

编写接口

//更新一个用户 int updateUser(User user);

编写sql语句

update mybatis.user set name=#{name},pwd=#{pwd} where id=#{id};

测试

@Test public void updateUser(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); mapper.updateUser(new User(4,"嘿嘿","1111")); sqlSession.commit(); sqlSession.close(); }

delete

编写接口

//删除一个用户 int deleteUser(int id);

编写sql语句

delete from mybatis.user where id = #{id};

测试

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