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

@RestControllerAdvice
public 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

@Component
public 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;
    }

}