如何处理请求映射中的@Valid违规？

Question

我在Java/Spring中有以下Rest控制器。将检查约束的验证。然而，这些都是在到达我的“bar”方法主体之前完成的。如何处理违规案件？我可以定制400个响应主体吗？

@RestController
@RequestMapping("foo")
public class FooController {

    @RequestMapping(value = "bar", method = RequestMethod.POST)
    public ResponseEntity<Void> bar(@RequestBody @Valid Foo foo) {
        //body part
        return ResponseEntity.status(HttpStatus.OK).build();
    }

}

Answer 1

您可以将BindingResult作为末尾的参数添加到方法签名中。

@RequestMapping(value = "bar", method = RequestMethod.POST)
public ResponseEntity<Void> bar(@RequestBody @Valid Foo foo, BindingResult bindingResult) 
{
    if (bindingResult.hasErrors()) {
        //do something if errors occured
        return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
    } 

    //body part
    return ResponseEntity.status(HttpStatus.OK).build();
}

Answer 2

您应该使用controllerAdvice，下面是一个示例（在kotlin中）：

@ControllerAdvice
open class ExceptionAdvice {

    @ExceptionHandler(MethodArgumentNotValidException::class)
    @ResponseBody
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    open fun methodArgumentNotValidExceptionHandler(request: HttpServletRequest, e: MethodArgumentNotValidException): ErrorDto {

        val errors = HashMap<String, String>()

        for (violation in e.bindingResult.allErrors) {
            if (violation is FieldError) {
                errors.put(violation.field, violation.defaultMessage)
            }
        }

        return ErrorDto(errors)
    }

    @ExceptionHandler(BindException::class)
    @ResponseBody
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    open fun bindExceptionHandler(request: HttpServletRequest, e: BindException): ErrorDto {

        val errors = HashMap<String, String>()

        for (violation in e.bindingResult.allErrors) {
            if (violation is FieldError) {
                errors.put(violation.field, violation.defaultMessage)
            }
        }

        return ErrorDto(errors)
    }
}

它允许处理控制器引发的异常，包括验证异常。