Spring 捕捉校验参数异常并统一处理

使用 @Validated ，@Valid ，@NotBlank 之类的，请自行百度，本文着重与捕捉校验失败信息并封装返回出去

参考：

https://mp.weixin.qq.com/s/EaZxYKyC4L_EofWdtyBCpw

https://www.jianshu.com/p/bcc5a3c86480

捕捉校验失败异常信息

@ControllerAdvice
public class WebExceptionHandler {

　　 //处理Get请求中 使用@Valid 验证路径中请求实体校验失败后抛出的异常，详情继续往下看代码
    @ExceptionHandler(BindException.class)
    @ResponseBody
    public ResponseVO BindExceptionHandler(BindException e) {
        String message = e.getBindingResult().getAllErrors().stream().map(DefaultMessageSourceResolvable::getDefaultMessage).collect(Collectors.joining());
        return new ResponseVO(message);
    }

    //处理请求参数格式错误 @RequestParam上validate失败后抛出的异常是javax.validation.ConstraintViolationException
    @ExceptionHandler(ConstraintViolationException.class)
    @ResponseBody
    public ResponseVO ConstraintViolationExceptionHandler(ConstraintViolationException e) {
        String message = e.getConstraintViolations().stream().map(ConstraintViolation::getMessage).collect(Collectors.joining());
        return new ResponseVO(message);
    }

    //处理请求参数格式错误 @RequestBody上validate失败后抛出的异常是MethodArgumentNotValidException异常。
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseBody
    public ResponseVO MethodArgumentNotValidExceptionHandler(MethodArgumentNotValidException e) {
        String message = e.getBindingResult().getAllErrors().stream().map(DefaultMessageSourceResolvable::getDefaultMessage).collect(Collectors.joining());
        return new ResponseVO(message);
    }
}

如下示例请求参数报错的话，会抛出 BindException 而不是  ConstraintViolationException 和 MethodArgumentNotValidException

@RestController
@RequestMapping("test")
public class TestController {

    @GetMapping("refund")
    public ResponseVO refund(@Valid RefundRequest request) throws Exception {
        return new ResponseVO();
    }
}

@Data
public class RefundRequest implements Serializable {
    @NotBlank(message = "订单号不能为空")
    private String orderId;
    @Min(value = 0, message = "已消费金额金额不能为负数")
    private int orderAmt;
}

如果多个请求参数都校验失败，则遇到第一个校验失败就抛出异常，接下来的异常参数不做校验，配置如下

@Configuration
public class WebConfig {
    @Bean
    public Validator validator() {
        ValidatorFactory validatorFactory = Validation.byProvider(HibernateValidator.class)
                .configure()
                //failFast的意思只要出现校验失败的情况，就立即结束校验，不再进行后续的校验。
                .failFast(true)
                .buildValidatorFactory();

        return validatorFactory.getValidator();
    }

    @Bean
    public MethodValidationPostProcessor methodValidationPostProcessor() {
        MethodValidationPostProcessor methodValidationPostProcessor = new MethodValidationPostProcessor();
        methodValidationPostProcessor.setValidator(validator());
        return methodValidationPostProcessor;
    }
}