mybatis中也提供了注解式开发方式，采用注解可以减少Sql语句的维护带来的成本

原则：简单sql可以注解，复杂sql使用xml

@Insert

// CarMapper.java
@Insert("insert into t_car values(null,#{carNum},#{brand},#{guidePrice},#{produceTime},#{carType})")
int insert(Car car);

//test文件
@Test
public void test(){SqlSession sqlSession = SqlSessionUtil.openSession();CarMapper mapper = sqlSession.getMapper(CarMapper.class);Car car = new Car(null,null,null,null,null,null,null);int count = mapper.insert(car);System.out.println(count);sqlSession.commit();sqlSession.close();
}

@Delete

@Delete( "delete from t_car where id = #{id}")
int deleteById(Long id);

//test文件
@Test
public void test2(){SqlSession sqlSession = SqlSessionUtil.openSession();CarMapper mapper = sqlSession.getMapper(CarMapper.class);int count = mapper.deleteById(5L);System.out.println(count);sqlSession.commit();sqlSession.close();
}

@Update

@Update("updeate t_car set car_num=#{carNum} , brand=#{brand} , guide_price=#{guidePrice} produce_time=#{produceTime} , car_type=#(carType} where id=#{id}" )
int update(Car car);

//test文件
@Test
public void test3(){SqlSession sqlSession = SqlSessionUtil.openSession();CarMapper mapper = sqlSession.getMapper(CarMapper.class);Car car = new Car(6L,null,null,null,null,null,null);int count = mapper.update(car);System.out.println(count);sqlSession.commit();sqlSession.close();
}

@Select

@select( "select * from t_car where id =#{id}")
Car selectById(Long id);

//test文件
@Test
public void test4(){SqlSession sqlSession = SqlSessionUtil.openSession();CarMapper mapper = sqlSession.getMapper(CarMapper.class);int count = mapper.select(5L);System.out.println(count);sqlSession.commit();sqlSession.close();
}

@Results

@Select( "select * from t_car where id = #{id}")
@Results({@Result(property = "id" , column = "id"),@Result(property = "carNum",column = "car_num"),@Result(property = "brand" , column = "brand")，@Result(property = "guidePrice" , column = "guide_price"),@Result(property = "produceTime" , column = "produce_time"),@Result(property = "carType", column = "car_type ")
})
Car selectById(Long id);