java - 添加绑定(bind)以进行验证

Question

我想创建用于验证 Java 对象的 Spring 端点。我试图实现这个例子:

https://www.baeldung.com/validation-angularjs-spring-mvc

我试过这个:

public class WpfPaymentsDTO {

    @NotNull
    @Size(min = 4, max = 15)
    private String card_holder;

    private String card_number;
    ....
}

终点:

 @PostMapping(value = "/payment/{unique_transaction_id}", consumes = { MediaType.APPLICATION_JSON_VALUE }, produces = { MediaType.APPLICATION_JSON_VALUE })
      public ResponseEntity<StringResponseDTO> handleWpfMessage(@PathVariable("unique_transaction_id") String unique_transaction_id,
          @RequestBody WpfPaymentsDTO transaction, BindingResult result, HttpServletRequest request) throws Exception {

        if (result.hasErrors()) {
            List<String> errors = result.getAllErrors().stream()
              .map(DefaultMessageSourceResolvable::getDefaultMessage)
              .collect(Collectors.toList());
            return new ResponseEntity<>(errors, HttpStatus.OK);
        } 

        return ResponseEntity.ok(new StringResponseDTO("test"));
      }

当使用提交 Angular 表单时，我想验证所有字段。但目前我收到此错误:Cannot infer type arguments for ResponseEntity<>

实现这个的正确方法是什么？

Answer 1

您缺少 @Valid 方法签名中的注释。如果您查看引用的示例，您会发现它用于 User。目的。

所以在你的情况下:

@Valid @RequestBody WpfPaymentsDTO transaction

您还在 ResponseEntity<T> 中返回了两种不同的类类型

1) ResponseEntity<StringResponseDTO>在验证成功的场景中

2) ResponseEntity<List<String>>在验证失败的情况下

以上是原因:

But currently I get this error: Cannot infer type arguments for ResponseEntity<>

如果您查看引用的示例，方法返回类型为 ResponseEntity<Object> .

所以你的方法应该改为:

  @PostMapping(value = "/payment/{unique_transaction_id}", 
     consumes = { MediaType.APPLICATION_JSON_VALUE }, 
     produces = { MediaType.APPLICATION_JSON_VALUE })
  public ResponseEntity<Object> handleWpfMessage(
                 @PathVariable("unique_transaction_id") String unique_transaction_id,
                 @Valid @RequestBody WpfPaymentsDTO transaction, 
                 BindingResult result, 
                 HttpServletRequest request) throws Exception {

更新:

Is there a way to find out for which variable the validation error is raised?

是的，您可以像这样得到所有字段绑定(bind)错误:

List<FieldError> errors = bindingResult.getFieldErrors();
for (FieldError error : errors ) {
    System.out.println ("Validation error in field: " + error.getField() 
                    + "! Validation error message: " + error.getDefaultMessage() 
                    + "! Rejected value:" + error.getRejectedValue());
}