一、统一异常处理的作用

　　在web应用中，请求处理时，出现异常是非常常见的。所以当应用出现各类异常时，进行异常的统一捕获或者二次处理(比如空指针异常或sql异常正常是不能外抛)是非常必要的，然后右统一异常处理方法统一返给前端。

对于非自定义的异常，在统一异常处理方法中，会转化为约定了响应的参数格式，如code（非0代表异常）、message，调用方根据错误码进行自己的业务逻辑。

二、统一异常处理方案一

@RestControllerAdvice和@ExceptionHandler的方式

@RestControllerAdvicepublic class BaseControllerAdvice {    private static final Logger logger = LoggerFactory.getLogger(BaseControllerAdvice.class);    public static final Pattern ERROR_MESSAGE_PATTERN = Pattern.compile("\\[(\\d{4})\\] (.*)");    public BaseControllerAdvice() {    }    @ExceptionHandler    public ApiResponse globalExceptionHandler(HttpServletRequest request, HttpServletResponse response, Exception ex) {        logger.error("检测到未捕捉异常：IP:{} invoke url:{} Exception:{}", new Object[]{request.getRemoteAddr(), request.getRequestURL(), ex.getClass().toGenericString(), ex}); 　　　　　//ApiResponse为自定义异常类　        ApiResponse apiResponse = new ApiResponse(ApiResponseCodeEnum.SYSTEM_EXCEPTION);        if (ex instanceof ApiException) {            Integer code = ((ApiException)ex).getCode();            return new ApiResponse(code, ex.getMessage());        } else {            if (StringUtils.isNotBlank(ex.getMessage())) {                Matcher matcher = ERROR_MESSAGE_PATTERN.matcher(ex.getMessage());                if (matcher.matches()) {                    logger.error(ex.getMessage(), ex);                    return apiResponse;                }            }            return apiResponse;        }    }}

 

三、统一异常处理方案二

HandlerExceptionResolver的方式

@Componentpublic class GlobalHandlerExceptionResolver implements HandlerExceptionResolver {    private static final Logger logger = LoggerFactory.getLogger(BaseControllerAdvice.class);    public static final Pattern ERROR_MESSAGE_PATTERN = Pattern.compile("\\[(\\d{4})\\] (.*)");    @Override    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response,  Object handler, Exception ex) {        ModelAndView modelAndView = new ModelAndView();        logger.error("检测到未捕捉异常：IP:{} invoke url:{} Exception:{}", new Object[]{request.getRemoteAddr(), request.getRequestURL(), ex.getClass().toGenericString(), ex});        ApiResponse apiResponse = new ApiResponse(ApiResponseCodeEnum.SYSTEM_EXCEPTION);        if (ex instanceof ApiException) {            Integer code = ((ApiException)ex).getCode();            apiResponse =new ApiResponse(code, ex.getMessage());        } else {            if (StringUtils.isNotBlank(ex.getMessage())) {                Matcher matcher = ERROR_MESSAGE_PATTERN.matcher(ex.getMessage());                if (matcher.matches()) {                    logger.error(ex.getMessage(), ex);                }            }        }        modelAndView.setView(new MappingJackson2JsonView());        modelAndView.addObject("code",apiResponse.getCode());        modelAndView.addObject("message",apiResponse.getMessage());        return modelAndView;    }}