Spring 数据 JPA：使用多个@PathVariable 检索数据

Question

I am trying to retrieve a user's particular order.

---

This is how I retrieve the user's order s in my OrderController

@GetMapping("/{id}/orders")
public List<Order> findAll(@PathVariable Long id) throws UserNotFoundException {
    Optional<User> existingUser = this.userRepository.findById(id);

    if (existingUser.isEmpty()) {
        throw new UserNotFoundException("User not found");
    }

    return existingUser.get().getOrders();
}

With the RequestMapping

@RestController
@RequestMapping("/api/users")
public class OrderController {(...)}

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This is the OneToMany relationship

User Entity

// ONE TO MANY
@OneToMany(mappedBy = "user")
private List<Order> orders;

Order Entity

// MANY TO ONE
@ManyToOne(fetch = FetchType.LAZY)
@JsonIgnore
private User user;

---

The UserRepository and OrderRepository interface, both extend JpaRepository

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I do manage to retrieve all the user's orders through Postman

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I am now wondering, how can I retrieve a user's particular order?

So for instance, as shown in the image let's say I would only like to retrieve the order with the id of 2, in this particular address:

http://localhost:8070/api/users/1/orders/2

How can I make it please?

Answer 1

Create an endpoint with

@GetMapping("/{id}/orders/{orderId}")

and return the particular order.

Create an OrderRepository and simply create the

public Order findByIdAndUserId(long orderId,long userId);

interface method for retrieving the given one.

Just a remark: you should validate that the given user is the same as the logged in one. What happen if I send a request to the backend, where I rewrite the user id to someone else's id?

Answer 2

try this,

    @GetMapping("/{userId}/orders/{orderId}")
    public Order findAll(@PathVariable Long userId, @PathVariable Long orderId) throws Exception {
        //your code
    }

Answer 3

Obviously you should had a Get mapping:

@GetMapping("/{userId}/orders/{orderId}")
public List<Order> findAll(@PathVariable Long userId, @PathVariable Long orderId) throws UserNotFoundException {
    ...
}

And for the requesting, you have three options:

1. Call you this.userRepository.findById(id) and filter after your order.
2. Create an OrderRepository to limit the request to the order table. But you need to have a reference to the user and you will probably not improve any performance. I would not advise that.
3. Add a query in your order repository to query the orderId for the userId:

---

@Repository
public interface UserRepository extends JpaRepository<.., ..> {
    @Query("select ... from User user join user.orders ... where ...user = :userId and order = :orderId")
    Order getUserOrder(@Param("userId") String userId, @Param("orderId") String orderId);
}

Anyway, You should create a service and inject it in the controller to encapsulate the search/filtering complexity and let you endpoints code clean ( @Autowired private OrderService orderService ):

@RestController
@RequestMapping("/api/users")
public class OrderController {
    @Autowired
    private OrderService orderService;
}

and:

@Service
public class OrderService {

}