java - Spring Boot 如何返回我自己的验证约束错误信息

Question

当我的请求出现问题时，我需要有自己的错误响应主体，我正在尝试使用 @NotEmpty 约束消息属性来返回错误消息，

这是我的类，它使用我需要的正文返回错误消息:

package c.m.nanicolina.exceptions;


import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.MissingServletRequestParameterException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.context.request.WebRequest;

@ControllerAdvice
public class CustomResponseEntityExceptionHandler {

    @ExceptionHandler(value = {MissingServletRequestParameterException.class})
    public ResponseEntity<ApiError> handleConflict(MissingServletRequestParameterException ex, WebRequest request) {
        ApiError apiError = new ApiError(ex.getMessage(), ex.getMessage(), 1000);
        return new ResponseEntity<ApiError>(apiError, null, HttpStatus.BAD_REQUEST);
    }
}

有了这个 CustomResponseEntityExceptionHandler，我可以在验证错误的情况下返回我自己的响应主体。

我现在正在尝试的是从验证约束中获取消息。

这是我的带有 NotEmpty 约束的 Controller :

package c.m.nanicolina.controllers;

import c.m.nanicolina.models.Product;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.constraints.NotEmpty;

@RestController
public class MinimumStockController {

    @RequestMapping(value = "/minimumstock")
    public Product product(
            @RequestParam(value = "product.sku") @NotEmpty(message = "Product.sku cannot be empty") String sku,
            @RequestParam(value = "stock.branch.id") String branchID) {
        return null;
    }
}

在我的异常(exception)情况下，我找不到获取该消息 Product.sku cannot be empty 并在我的错误响应中显示它的方法。

我还检查了类 MissingServletRequestParameterException 并且有返回默认消息的方法 getMessage。

Answer 1

是的，它是可行的 & spring 很好地支持它。您只是缺少一些在 spring 中启用它的配置。

• Use Spring@Validated annotation to enable spring to validate controller
• Handle ConstraintViolationException in your ControllerAdvice to catch all failed validation messages.
• Mark required=false in @RequestParam, so it will not throw MissingServletRequestParameterException and rather move to next step of constraint validation.

@ControllerAdvice
public class CustomResponseEntityExceptionHandler {

    @ExceptionHandler
  public ResponseEntity<ApiError> handle(ConstraintViolationException exception) {
        //you will get all javax failed validation, can be more than one
        //so you can return the set of error messages or just the first message
        String errorMessage = new ArrayList<>(exception.getConstraintViolations()).get(0).getMessage();
       ApiError apiError = new ApiError(errorMessage, errorMessage, 1000);    
       return new ResponseEntity<ApiError>(apiError, null, HttpStatus.BAD_REQUEST);
  }
}



@RestController
@Validated
public class MinimumStockController {

    @RequestMapping(value = "/minimumstock")
    public Product product(
            @RequestParam(value = "product.sku", required=false) @NotEmpty(message = "Product.sku cannot be empty") String sku,
            @RequestParam(value = "stock.branch.id", required=false) String branchID) {
        return null;
    }
}

注意 MissingServletRequestParameterException 将无法访问 javax 验证消息，因为它在请求生命周期中发生约束验证之前抛出。