Mybatis一对多关联关系映射实现过程解析

/**
 * 订单持久化类
 */
public class Orders {
 private Integer id;
 private String number;
 setter/getter方法
}

/**
*用户持久化类
*/
public class User {
 private Integer id;
 private String username;
 private String address;
 private List ordersList;//用户关联的订单
 setter/getter方法
}

/**
 * 用户Mapper接口
 */
public interface UserMapper {
 //用户和订单为一对多关系，那么此时应该返回一个用户list里面包含了订单信息
 List userOrdersinfo(int id);//通过用户id返回它的订单信息
}

<?xml version="1.0" encoding="UTF-8" ?>



 
  
  
  
  
  
   
   
  
 
 
 
  select u.*,o.id as orders_id,o.number
  from tb_user u,tb_orders o
  where u.id=o.user_id and u.id=#{id}
 

/**
 * 用户业务层接口
 */
public interface UserWithOrdersInfo {
 List selectUserOrdersInfo(int id);
}

@Service
public class UserWithOrdersInfoImpl implements UserWithOrdersInfo {
 @Autowired
 private UserMapper userMapper;

 @Override
 public List selectUserOrdersInfo(int id) {
  return userMapper.userOrdersinfo(id);
 }
}

@Controller
public class UserOrdersController {
 @Autowired
 private UserWithOrdersInfo userWithOrdersInfo;
 @RequestMapping("/userordersinfo/{id}")
 public String getUserOrdersInfo(@PathVariable int id, Model model){
  model.addAttribute("userordersinfo",userWithOrdersInfo.selectUserOrdersInfo(id));
  return "userordersinfo";
 }
}

 
 



 

 

  
用户id
  
姓名
  
用户地址
  
订单id
  
订单号
 
 
 

  
用户id
  
用户姓名
  
用户地址
  
订单id
  
订单号
  
订单id
  
订单号