如何自动在django-cities中填充状态下拉列表-选择一个国家时如何？

Question

我已成功将Django city light集成到我的应用程序中，并且进行了所有迁移，同时，我还在用户个人资料表单中添加了country字段。如何根据用户选择的国家和州自动填充州和城市字段。

当前型号： ```

@RestController
@RequestMapping("orders")
public class OrderController {

@Autowired
private OrderRepository orderRepository;

@GetMapping
public Flux<Order> getAllOrders() {
    return orderRepository.findAll();
}

@PostMapping
public Mono<Tweet> createOrder(@Valid @RequestBody Order order) {
    return orderRepository.save(order);
}

@GetMapping("{id}")
public Mono<ResponseEntity<Order>> getOrderById(@PathVariable(value = "id") String orderId) {
    return orderRepository.findById(orderId)
            .map(savedOrder -> ResponseEntity.ok(savedOrder))
            .defaultIfEmpty(ResponseEntity.notFound().build());
}

@PutMapping("{id}")
public Mono<ResponseEntity<Order>> updateTweet(@PathVariable(value = "id") String orderId,
                                               @Valid @RequestBody Order order) {
    return orderRepository.findById(orderId)
            .flatMap(existingOrder -> {
                existingOrder.setDesc(order.getDesc());
                return orderRepository.save(existingOrder);
            })
            .map(updatedOrder -> new ResponseEntity<>(updatedOrder, HttpStatus.OK))
            .defaultIfEmpty(new ResponseEntity<>(HttpStatus.NOT_FOUND));
}

@DeleteMapping("{id}")
public Mono<ResponseEntity<Void>> deleteOrder(@PathVariable(value = "id") String orderId) {

    return orderRepository.findById(orderId)
            .flatMap(existingOrder ->
                    orderRepository.delete(existingOrder)
                        .then(Mono.just(new ResponseEntity<Void>(HttpStatus.OK)))
            )
            .defaultIfEmpty(new ResponseEntity<>(HttpStatus.NOT_FOUND));
}

// Orders are Sent to the client as Server Sent Events
@GetMapping(value = "/stream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
public Flux<Order> streamAllOrders() {
    return orderRepository.findAll();
}
}

```