mybits 注解

             MyBatis注解位于org.apache.ibatis.annotations包下，常用注解如下

             1 select  映射查询sql语句 2 insert 映射插入语句  3  update 映射更新语句  4 delete 映射删除语句  5 result  在列和属性之间的单独结果映射，属性包括id  column one many，等  id是一个布尔值，表示是否用于主键映射，one是单独的联系和xml中<association>相似 ，mang对集合而言，和xml中的<collection>相似   4 results 多个结果映射（result）列表 。 5 optins提供配置选项的附加值，在映射语句上作为附加功能配置出现。6 当映射方法需要多个参数时，应用于映射器方法参数来给每个参数娶一个名字，否则多参数将会以他们的顺序位置和SQL语句的表达式进行映射

             注解使用  @select   @insert @update  @delete 可以完成常见的增删改查功能sql语句映射

             

public interface AUserMapper {@Insert("INSERT INTO USER(username,sex, birthday, address) VALUES(#{username},#{sex},#{birthday},#{address})")@Options(useGeneratedKeys=true, keyProperty="id")int saveUser(User user);@Delete("delete from user where id=#{id}")int removeUser(@Param("id") Integer id);@Update("update user set username=#{username}, birthday=#{birthday}, sex=#{sex}, address=#{address} where id=#{id}")void modifyUser(User user);@Select("select * from user where id=#{id}")@Results({@Result(id=true, column="id", property="id"),@Result(column="username", property="username"),@Result(column="birthday", property="birthday"),@Result(column="sex", property="sex"),@Result(column="address", property="address"),})User selectUserById(Integer id);@Select("select * from user")List<User> selectAllUser();}

@Testpublic void saveUserTest() throws Exception{//读取配置文件//全局配置文件的路径String resource = "SqlMapConfig.xml";InputStream inputStream = Resources.getResourceAsStream(resource);//创建SqlSessionFactorySqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//创建SqlSessionSqlSession sqlSession = sqlSessionFactory.openSession();//调用SqlSession的增删改查方法//第一个参数：表示statement的唯一标示AUserMapper mapper = sqlSession.getMapper(AUserMapper.class);User user = new User();user.setUsername("whe");user.setSex("i");user.setAddress("ds");mapper.saveUser(user);System.out.println(user.getId());sqlSession.close();}

  一对一   一个订单只有一个用户

         

public interface UserMapper {@Select("select * from user where id=#{id}")User selectUserById(Integer id);}

public interface OrderMapper {@Select("select * from orders where id=#{id}")@Results({@Result(id=true, column="id", property="id"),@Result(column="number", property="number"),@Result(column="createtime", property="createtime"),@Result(column="note", property="note"),@Result(column="user_id", property="user",    one =@One(select="com.itheima.ms.mapper.UserMapper.selectUserById",    fetchType=FetchType.EAGER))})Orders selectOrdersById(Integer id);}

           MyBatis 注解支持动态SQL ， @selectprovider  @insertprovider @updateprovider  @deleteprovider 来帮助构建动态sql语句，org.apache.ibatis.jdbc.SQL用来拼接sql语句，Privoder方方法可接收ava对象，map对象

                 @SelectProvider(type=com.itheima.ms.mapper.UserSqlPrivoder.class, method="selectWithPar")
    List <User> selectUserById(Map<String, Object> map);
               

public class UserSqlPrivoder {public String selectWithPar(final Map<String, Object> map){return new SQL(){{SELECT("*");FROM("user");if (map.get("id") != null){WHERE(" id=#{id}");}}}.toString();}}