项目中对异常的处理(两种方式)

1:切面中对异常的处理

切面中的通知包括:前置通知(Before advice)/后置通知(After advice)/环绕通知(Around advice)/异常通知(After throwing advice)/正常返回通知(After returning advice)

其中:后置通知与正常返回通知的区别

后置通知不管抛出异常与否都会执行,正常返回通知在连接点正常执行后,没有抛出异常才会执行.

异常通知是在出现异常后才会执行的切面.

直接上异常通知的代码

@Aspect
@Component
public class ControllerExceptionAspect {
    private static ObjectMapper objectMapper = new ObjectMapper();
    @Pointcut("@annotation(org.springframework.web.bind.annotation.RequestMapping)")
    private void webPoint(){

    }

    /**
     * 异常通知
     * @param e
     */
    @AfterThrowing(pointcut = "webPoint()",throwing = "e")
    public void handlerException(Exception e){
        e.printStackTrace();
        writeContent(e.getMessage());
    }

    /**
     * 对异常进行处理,统一捕获返回到前端显示
     * @param content
     */
    private void writeContent(String content) {
        HttpServletResponse response = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes())
                .getResponse();
        response.reset();
        response.setCharacterEncoding("UTF-8");
        response.setHeader("Content-Type", "text/plain;charset=UTF-8");
        response.setHeader("icop-content-type", "exception");
        PrintWriter writer = null;
        try {
            writer = response.getWriter();
        } catch (IOException e) {
            e.printStackTrace();
        }
        MessageDto messageDto = new MessageDto();
        messageDto.setCode("400");
        messageDto.setMessage(content);
        try {
            writer.print(objectMapper.writeValueAsString(messageDto));
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            System.out.println("向前端传送错误数据失败!");
        }
        writer.flush();
        writer.close();
    }
}

2:使用@ExceptionHandler注解

使用该注解可以针对不同的异常进行不同逻辑的处理,上面的方式只能有一种处理逻辑.

@Component
@RestControllerAdvice
@Log4j2
public class GlobalExceptionAdvance {

    @Autowired
    private CoreProperties coreProperties;

    /**
     * 400 请求动词错误
     */
    @ExceptionHandler(HttpRequestMethodNotSupportedException.class)
    public RequestResult handle(HttpRequestMethodNotSupportedException e) {
        return RequestResult.failure(ResultCode.BAD_REQEUST,
                "请求动词不受支持，当前为[" + e.getMethod() + "]，正确为" + Arrays.toString(e.getSupportedMethods()));
    }

    /**
     * 400 请求Content-Type错误 往往是因为后端的@RequestBody和前端的application/json没有同时指定或同时不指定。
     */
    @ExceptionHandler(HttpMediaTypeNotSupportedException.class)
    public RequestResult handle(HttpMediaTypeNotSupportedException e) {
        return RequestResult.failure(ResultCode.BAD_REQEUST,
                "Content-Type错误，当前为[" + e.getContentType().toString().replace(";charset=UTF-8", "") +
                        "]，正确为[application/json]");
    }

    /**
     * 400 缺少RequestParam参数
     * 
     * 但以下情况不会被捕获：
     * /user?type
     * /user?type=
     * 
     */
    @ExceptionHandler(MissingServletRequestParameterException.class)
    public RequestResult handle(MissingServletRequestParameterException e) {
        return RequestResult.failure(ResultCode.BAD_REQEUST, "缺少请求参数" + e.getParameterName());
    }

    /**
     * 400 RequestParam参数类型错误
     */
    @ExceptionHandler(MethodArgumentTypeMismatchException.class)
    public RequestResult handle(MethodArgumentTypeMismatchException e) {
        return RequestResult.failure(ResultCode.BAD_REQEUST, e.getName() + "类型错误");
    }

    /**
     * 400 RequestParam参数没有通过注解校验（控制器声明@Validated时）
     */
    @ExceptionHandler(ConstraintViolationException.class)
    public RequestResult handle(ConstraintViolationException e) {
        Set> cvs = e.getConstraintViolations();
        RequestTrack requestTrack = Requests.getRequestTrack();
        String[] paramNames = requestTrack.getParameterNames();
        Object[] paramValues = requestTrack.getParameterValues();
        List invalids = new ArrayList<>();
        for (ConstraintViolation cv : cvs) {
            // 参数路径
            PathImpl pathImpl = (PathImpl) cv.getPropertyPath();
            // 参数下标
            int paramIndex = pathImpl.getLeafNode().getParameterIndex();
            invalids.add(Invalid.builder().name(paramNames[paramIndex]).value(paramValues[paramIndex]).cause(
                    cv.getMessage()).build());
        }
        return RequestResult.failure(ResultCode.BAD_REQEUST, "数据校验未通过").setData(invalids);
    }

    /**
     * 400 RequestParam参数没有通过注解校验（multi-param且声明@Valid时）
     */
    @ExceptionHandler(BindException.class)
    public RequestResult handle(BindException e) {
        List invalids = new ArrayList<>();
        for (FieldError fieldError : e.getFieldErrors()) {
            invalids.add(Invalid.builder().name(fieldError.getField()).value(fieldError.getRejectedValue())
                    .cause(fieldError.getDefaultMessage()).build());
        }
        return RequestResult.failure(ResultCode.BAD_REQEUST, "数据校验未通过").setData(invalids);
    }

    /**
     * 400 请求Body格式错误
     * 
     * 以下情况时，会被捕获：
     * alkdjfaldfjlalkajkdklf
     * (空)
     * {"userAge"="notNumberValue"}
     * 
     */
    @ExceptionHandler(HttpMessageNotReadableException.class)
    public RequestResult httpMessageNotReadable() {
        return RequestResult.failure(ResultCode.BAD_REQEUST, "请求Body不可读。可能是JSON格式错误，或JSON不存在，或类型错误");
    }

    /**
     * 400 请求Body内字段没有通过注解校验（形参声明@Valid时）
     */
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public RequestResult handle(MethodArgumentNotValidException e) {
        BindingResult bindingResult = e.getBindingResult();
        List invalids = new ArrayList<>();
        for (FieldError fieldError : bindingResult.getFieldErrors()) {
            invalids.add(Invalid.builder().name(fieldError.getField()).value(fieldError.getRejectedValue()).cause(
                    fieldError.getDefaultMessage()).build());
        }
        return RequestResult.failure(ResultCode.BAD_REQEUST, "数据校验未通过").setData(invalids);
    }

    /**
     * 400 成功绑定并通过校验的请求方法参数，没有通过切面的额外校验（如?temp&foo=这样的情况）
     */
    @ExceptionHandler(ExtraInvalidException.class)
    public RequestResult handle(ExtraInvalidException e) {
        return RequestResult.failure(ResultCode.BAD_REQEUST, "数据校验未通过").setData(e.getInvalids());
    }

    /**
     * 401 未登录
     */
    @ExceptionHandler(UnsignedException.class)
    public RequestResult handleUnsignException(UnsignedException e) {
        return RequestResult.failure(ResultCode.UNSIGNED, e.getMessage());
    }

    /**
     * 403 没权限或是请求actuator时提供的token不正确
     */
    @ExceptionHandler(AuthorizationException.class)
    public RequestResult handleAuthorizationException() {
        return RequestResult.failure(ResultCode.FORBIDDEN);
    }

    /**
     * 404 找不到请求
     */
    @ExceptionHandler(RequestNotFoundException.class)
    public RequestResult handleRequestNotFoundException() {
        return RequestResult.failure(ResultCode.NOT_FOUND);
    }

    /**
     * 1001 业务异常
     */
    @ExceptionHandler(ServiceException.class)
    public RequestResult handle(ServiceException e) {
        return RequestResult.failure(ResultCode.SERVICE_ERROR, e.getMessage());
    }

    /**
     * 500 内部BUG
     * 
     * 控制层上方发生的BUG（如过滤器中的BUG），无法返回标识符。因为没有进入切面
     * 控制层下方发生的BUG（如果业务层、持久层的BUG），能够返回标识符
     * 
     */
    @ExceptionHandler(Throwable.class)
    public RequestResult handle(Throwable e) {
        RequestTrack track = Requests.getRequestTrack();
        RequestResult requestResult;
        if (track == null) {
            log.error("统一异常处理被击穿！", e);
            requestResult = RequestResult.failure(ResultCode.INTERNAL_ERROR);
        } else {
            String insignia = track.getInsignia();
            log.error("统一异常处理被击穿！标识：" + insignia, e);
            requestResult = RequestResult.failure(ResultCode.INTERNAL_ERROR, "内部错误（" + insignia + "）");
        }
        // 详细错误信息
        if (coreProperties.isDebug()) {
            String msg = e.getMessage();
            if (msg == null) {
                msg = e.getClass().getSimpleName();
            }
            if (msg.length() > 200) {
                msg = msg.substring(0, 200) + " ...";
            }
            requestResult.setMessage(requestResult.getMessage() + "，详细信息（" + msg + "）");
        }
        return requestResult;
    }

}