使用@ControllerAdvice如何返回给前端对应错误码

水深无声 2022-03-02 11:30 359阅读 0赞

@ControllerAdvice可以捕获spring应用下面未被捕获异常，下面是常见代码：

@ExceptionHandler(value = Exception.class)  
    @**ResponseStatus**(HttpStatus.INTERNAL\_SERVER\_ERROR)  
    public String errorHandler(Exception ex) \{  
        ApiResultVo<String> resultVo = new ApiResultVo<>();  
        resultVo.setErrorCode(500);  
        resultVo.setErrorMsg(ex.getMessage());  
        return JSON.toJSONString(resultVo);  
    \}  
      
    @ExceptionHandler(value = MyException.class)  
    @**ResponseStatus**(HttpStatus.INTERNAL\_SERVER\_ERROR)  
    public String myExceptionHandler(MyException ex) \{  
        ApiResultVo<String> resultVo = new ApiResultVo<>();  
        resultVo.setErrorCode(401);  
        resultVo.setErrorMsg(ex.getMessage());  
        return JSON.toJSONString(resultVo);  
    \}

我们在对应异常处理的上面加上ResponseStatus注解就能将系统异常转换为对应的Http状态码，这部分工作由ResponseStatusExceptionResolver这个类完成，下面是关键代码：

protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response,  
            Object handler, Exception ex) \{

ResponseStatus responseStatus = AnnotatedElementUtils.findMergedAnnotation(ex.getClass(), ResponseStatus.class);  
        if (responseStatus != null) \{  
            try \{  
                return **resolveResponseStatus**(responseStatus, request, response, handler, ex);  
            \}  
            catch (Exception resolveEx) \{  
                logger.warn("Handling of @ResponseStatus resulted in Exception", resolveEx);  
            \}  
        \}  
        else if (ex.getCause() instanceof Exception) \{  
            ex = (Exception) ex.getCause();  
            return doResolveException(request, response, handler, ex);  
        \}  
        return null;  
    \}

protected ModelAndView **resolveResponseStatus**(ResponseStatus responseStatus, HttpServletRequest request,  
            HttpServletResponse response, Object handler, Exception ex) throws Exception \{

int statusCode = responseStatus.code().value();  
        String reason = responseStatus.reason();  
        if (!StringUtils.hasLength(reason)) \{  
            **response.sendError**(statusCode);  
        \}  
        else \{  
            String resolvedReason = (this.messageSource != null ?  
                    this.messageSource.getMessage(reason, null, reason, LocaleContextHolder.getLocale()) :  
                    reason);  
            response.sendError(statusCode, resolvedReason);  
        \}  
        return new ModelAndView();  
    \}