@Insert @Update @Delete @Select @Result @Results @One @Many
public interface UserMapper { @Insert("insert into user values(#{id},#{username},#{password},#{birthday})") public void save(User user); @Update(" update user set username=#{username}, password=#{password} where id=#{id}") public void update(User user); @Delete("delete from user where id=#{id}") public void delete(int id); @Select("select * from user where id=#{id}") public User findById(int id); @Select("select * from user") public List<User> findAll(); }
加载映射关系， 指定接口所在包
<mappers> <package name="com.bearpx.spring.mybatis.dao"></package> </mappers>
| 注解 | 说明 |
| @Results |
代替<resultMap>标签，可以使用单个@Result注解，也可以使用@Result集合。 使用格式： @Results({@Result(), @Result()}) 或 @Results(@Result()) |
| @Result |
代替<id>和<result>标签。 @Result属性介绍： column： 数据库的列名 property： 需要装配的属性名 one： 需要使用的@One注解（@Result(one=@One)()） many： 需要使用的@Many注解（@Result (many=@many)()） |
| @One（一对一） |
代替<assocation>标签，是多表查询的关键，在注解中用来指定子查询返回单一对象。 @One注解属性介绍： select： 指定用来多表查询的sqlmapper 使用格式： @Result(column="", property="", one=@One(select="")) |
| @Many（多对一） |
代替<collection>标签，是多表查询的关键，在注解中用来指定子查询返回对象集合。 使用格式： @Result（column="", property="", many=@Many(select="")） |
@Select("select *,o.id oid from orders o, user u where o.uid = u.id")
@Results({
@Result(column = "oid",property = "id"),
@Result(column = "ordertime",property = "ordertime"),
@Result(column = "total",property = "total"),
@Result(column = "uid",property = "user.id"),
@Result(column = "username",property = "user.username"),
@Result(column = "password",property = "user.password")
})
public List<Order> findAll();
@Select("select * from orders")
@Results({
@Result(column = "id",property = "id"),
@Result(column = "ordertime",property = "ordertime"),
@Result(column = "total",property = "total"),
@Result(
property = "user", // 要封装的属性名称
column = "uid", // 根据哪个字段去查询user表的数据
javaType = User.class, // 要封装的实体类型
one = @One(select = "com.bearpx.spring.mybatis.dao.UserMapper.findById") // 查询哪个接口的方法获取数据
)
})
public List<Order> findAll2();
@Select("select * from user")
@Results({
@Result(id=true, column = "id",property = "id"),
@Result(column = "username",property = "username"),
@Result(column = "password",property = "password") ,
@Result(
property = "orderList",
column = "id",
javaType = List.class,
many = @Many(select="com.bearpx.spring.mybatis.dao.OrderMapper.findByUid")
)
})
public List<User> findUserAndOrderAll();
OrderMapper接口
@Select("select * from orders where uid=#{uid}")
public List<Order> findByUid(int uid);
@Select("select * from user")
@Results({
@Result(id=true, column = "id",property = "id"),
@Result(column = "username",property = "username"),
@Result(column = "password",property = "password") ,
@Result(
property = "roleList",
column = "id",
javaType = List.class,
many = @Many(select="com.bearpx.spring.mybatis.dao.RoleMapper.findByUid")
)
})
public List<User> findUserAndRoleAll();
public interface RoleMapper { @Select("select * from sys_user_role ur,sys_role r where ur.roleId = r.id and ur.userId=#{uid}") public List<Role> findByUid(int uid); }
原文：https://www.cnblogs.com/kingdomer/p/14032749.html