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軟件開發過程中，不可避免的是需要處理各種異常，所以代碼中就會出現大量的 try {...} catch {...} finally {...} 代碼塊，不僅有大量的冗餘代碼，而且還影響代碼的可讀性。
另一個就是面對業務異常的情況，我們經常需要將業務異常結果組裝成統一的信息返回給前端進行提示。
假如我們在每個接口中都去包裝異常信息進行返回就會讓代碼變得很冗餘且混亂。在我司的實際項目開發過程中，我們會巧用斷言去簡化代碼。
假設我們定義的標準接口響應實體為 ApiResult：@Data@Builder@NoArgsConstructor@AllArgsConstructorpublicclassApiResult<T>implementsSerializable{privatestaticfinallongserialVersionUID=411731814484355577L;privateintresponseCode;privateStringresponseMsg;privatebooleanisSuccess;privateTdata;publicStringtoString(){return"ApiResult(responseCode="+this.getResponseCode()+",responseMsg="+this.getResponseMsg()+",isSuccess="+this.isSuccess()+",data="+this.getData()+")";}}那麼我們接口處理業務邏輯時代碼就會變成這樣，看起來非常多代碼：publicApiResultcancelService(@PathVariableLongserviceOrderId){ServiceOrderserviceOrder=serviceOrderMapper.selectByPrimaryKey(serviceOrderId);ApiResultresult=newApiResult<>();if(ObjectUtil.isNull(serviceOrder)){result.setSuccess(false);result.setResponseCode(ErrorCodeEnum.FAIL.getCode());result.setResponseMsg("查無此服務單");returnresult;}if(serviceOrder.getOrderStatus().equals(cancelOrderStatus)){result.setSuccess(false);result.setResponseCode(ErrorCodeEnum.FAIL.getCode());result.setResponseMsg("已取消的服務單不允許再次取消");returnresult;}if(serviceOrder.getSortOrderId()!=null){result.setSuccess(false);result.setResponseCode(ErrorCodeEnum.FAIL.getCode());result.setResponseMsg("已配置物料的服務單不允許取消");returnresult;}//...othercheck//...dosomethingreturnresult;}然後在上面這個代碼基礎上，我們可以觀察到，裡面其實有非常多的重複代碼，完全可以把它們裝到 ApiResult 裡面。
這也是我看到很多開源框架的處理方式（PS：所以我第一個自己寫的框架也是這麼處理的）
在原 ApiResult 實體中增加一些公用的處理方法：publicstaticApiResult<String>success(){returnsuccess("success");}publicstatic<T>ApiResult<T>success(Tdata){return(newApiResult()).setResponseCode(0).setResponseMsg("操作成功").setSuccess(true).setData(data);}publicstaticApiResult<String>fail(){returnfail(-1);}publicstaticApiResult<String>fail(intcode){returnfail(code,"fail");}publicstatic<T>ApiResult<T>fail(Tdata){returnfail(-1,data);}publicstatic<T>ApiResult<T>fail(intcode,Tdata){return(newApiResult()).setResponseCode(code).setResponseMsg("操作失敗").setSuccess(false).setData(data);}publicstatic<T>ApiResult<T>success(intcode,Stringmessage,Tdata){return(newApiResult()).setResponseCode(code).setResponseMsg(message).setSuccess(true).setData(data);}publicstatic<T>ApiResult<T>fail(intcode,Stringmessage,Tdata){return(newApiResult()).setResponseCode(code).setResponseMsg(message).setSuccess(false).setData(data);}然後業務邏輯處理就變成這樣了，看起來還不錯是不是：/***取消服務單(不用斷言)*/publicApiResultcancelService(LongserviceOrderId){ServiceOrderserviceOrder=serviceOrderMapper.selectByPrimaryKey(serviceOrderId);ApiResultresult=newApiResult<>();if(ObjectUtil.isNull(serviceOrder)){result=ApiResult.fail(ErrorCodeEnum.FAIL.getCode(),"查無此服務單");returnresult;}if(serviceOrder.getOrderStatus().equals(cancelOrderStatus)){result=ApiResult.fail(ErrorCodeEnum.FAIL.getCode(),"已取消的服務單不允許再次取消");returnresult;}if(serviceOrder.getSortOrderId()!=null){result=ApiResult.fail(ErrorCodeEnum.FAIL.getCode(),"已配置物料的服務單不允許取消");returnresult;}//...othercheck//...dosomethingreturnresult;}但是我們可以用異常處理類+斷言處理得更加簡化。
@Slf4j@ControllerAdvicepublicclassGlobalExceptionHandler{@ExceptionHandler(value=BusinessException.class)@ResponseBodypublicResponseBeanbusinessExceptionHandler(BusinessExceptione){log.info("businesserror:{}",e.getMessage(),e);if(e.getCode()==-1){returnResponseBean.error(ApiCode.SERVICE_ERROR.getValue(),ApiCode.SERVICE_ERROR.getMessage());}returnResponseBean.error(e.getCode(),e.getMessage());}}/***業務異常，異常信息會返回到前端展示給用戶**@date2020/12/1514:18*/publicclassBusinessExceptionextendsRuntimeException{privatestaticfinallongserialVersionUID=-5770538329754222306L;privateintcode=1;privateLevellevel;publicBusinessException(intcode,Stringmessage,Throwablecause){super(message,cause);this.code=code;}publicBusinessException(Stringmessage){super(message);}publicBusinessException(Levellevel,Stringmessage){super(message);this.level=level;}publicBusinessException(Throwablecause){super(cause);}publicBusinessException(intcode,Stringmessage){super(message);this.code=code;}publicintgetCode(){returnthis.code;}publicfinalLevelgetLevel(){returnthis.level;}}publicclassAssertUtilextendscn.com.bluemoon.common.web.exception.AssertUtil{publicAssertUtil(){}/***服務調用異常*@paramexpression*@parammessage*/publicstaticvoidisTrueServiceInvoke(booleanexpression,Stringmessage){if(!expression){thrownewServiceInvokeException(message);}}/***拋出異常(默認錯誤1000)*@parammessage*/publicstaticvoidbusinessInvalid(Stringmessage){thrownewBusinessException(ApiCode.SERVICE_ERROR.getValue(),message);}/***表達式為真即拋出異常(默認錯誤1000)**@paramexpression*@parammessage*/publicstaticvoidbusinessInvalid(booleanexpression,Stringmessage){if(expression){thrownewBusinessException(ApiCode.SERVICE_ERROR.getValue(),message);}}/***表達式為真即拋出異常**@paramexpression*@parammessage*/publicstaticvoidbusinessInvalid(booleanexpression,intcode,Stringmessage){if(expression){thrownewBusinessException(code,message);}}}/***取消服務單*/publicApiResultcancelService(@PathVariableLongserviceOrderId){ServiceOrderserviceOrder=serviceOrderMapper.selectByPrimaryKey(serviceOrderId);AssertUtil.businessInvalid(ObjectUtil.isNull(serviceOrder),"查無此服務單");AssertUtil.businessInvalid(serviceOrder.getOrderStatus().equals(cancelOrderStatus),"查無此服務單");AssertUtil.businessInvalid(serviceOrder.getSortOrderId()!=null,"查無此服務單");//...othercheck//...dosomethingreturnApiResult.success();}最後，我們可以看到我們的接口由 19 行的業務檢查代碼簡化到了 3 行。這只是單接口的情況下，在業務多且複雜的情況下能給我們節省更多的開發時間，把精力集中在核心業務上。
/***統一異常處理*/@Slf4j@ControllerAdvicepublicclassGlobalExceptionHandler{@ExceptionHandler(value=AssertException.class)@ResponseBodypublicResponseBeanbootExceptionHandler(AssertExceptione){ApiCodeapiCode=ApiCode.getObjectByValue(e.getCode());log.error("businesserror:{}",e.getMessage(),e);if(e.getCode()==-1){returnResponseBean.error(ApiCode.SERVICE_ERROR.getValue(),ApiCode.SERVICE_ERROR.getMessage());}returnResponseBean.error(apiCode.getValue(),e.getMessage());}@ExceptionHandler(value=com.alibaba.fastjson.JSONException.class)publicResponseBeanalibabaJsonExceptionHandler(com.alibaba.fastjson.JSONExceptione){ResponseBeanresponse=newResponseBean(false,ApiCode.PARAM_FORMAT_INCORR.getValue(),ApiCode.PARAM_FORMAT_INCORR.getMessage()+e.getMessage(),null);log.error("1102",e);returnresponse;}@ExceptionHandler(value=JSONException.class)@ResponseBodypublicResponseBeanjsonExceptionHandler(JSONExceptione){ResponseBeanresponse=newResponseBean(false,ApiCode.PARAM_FORMAT_INCORR.getValue(),ApiCode.PARAM_FORMAT_INCORR.getMessage()+e.getMessage(),null);log.error(ApiCode.PARAM_FORMAT_INCORR.getValue()+"",e);returnresponse;}@ExceptionHandler(value=JsonParseException.class)@ResponseBodypublicResponseBeanjsonParseExceptionHandler(JsonParseExceptione){ResponseBeanresponse=newResponseBean(false,ApiCode.PARAM_FORMAT_INCORR.getValue(),String.format(ApiCode.PARAM_FORMAT_INCORR.getMessage()+":%s",e.getMessage()),null);log.error(ApiCode.PARAM_FORMAT_INCORR.getValue()+"",e);returnresponse;}@ExceptionHandler(value=Exception.class)@ResponseBodypublicResponseBeanexceptionHandler(Exceptione){ResponseBeanresponse=newResponseBean(false,ApiCode.SERVICE_ERROR.getValue(),ApiCode.SERVICE_ERROR.getMessage(),null);log.error(ApiCode.SERVICE_ERROR.getValue()+"",e);returnresponse;}@ExceptionHandler(value=MethodArgumentTypeMismatchException.class)@ResponseBodypublicResponseBeanexceptionHandle(MethodArgumentTypeMismatchExceptione){ResponseBeanresponse=newResponseBean(false,ApiCode.PARAM_FORMAT_INCORR.getValue(),String.format(ApiCode.PARAM_FORMAT_INCORR.getMessage()+":%s",e.getMessage()),null);log.error(ApiCode.PARAM_FORMAT_INCORR.getValue()+"",e);returnresponse;}@ExceptionHandler(value=WebException.class)@ResponseBodypublicResponseBeanexceptionHandler(WebExceptione){ResponseBeanresponse=newResponseBean(e.getIsSuccess(),e.getResponseCode(),e.getResponseMsg(),null);log.error(e.getResponseCode()+"",e);returnresponse;}@ExceptionHandler(value=IllegalArgumentException.class)@ResponseBodypublicResponseBeanexceptionHandler(IllegalArgumentExceptione){log.error("illegalrequest:{}",e.getMessage(),e);returnResponseBean.error(ApiCode.PARAM_INVALID.getValue(),ApiCode.PARAM_INVALID.getMessage());}@ExceptionHandler(value=ServiceInvokeException.class)@ResponseBodypublicResponseBeanexceptionHandler(ServiceInvokeExceptione){log.error("serviceInvokeerrorrequest:{}",e.getMessage(),e);returnResponseBean.error(ApiCode.SERVICE_ERROR.getValue(),ApiCode.SERVICE_ERROR.getMessage());}@ExceptionHandler(value=BusinessException.class)@ResponseBodypublicResponseBeanbusinessExceptionHandler(BusinessExceptione){log.info("businesserror:{}",e.getMessage(),e);if(e.getCode()==-1){returnResponseBean.error(ApiCode.SERVICE_ERROR.getValue(),ApiCode.SERVICE_ERROR.getMessage());}returnResponseBean.error(e.getCode(),e.getMessage());}@ResponseBody@ExceptionHandler(MethodArgumentNotValidException.class)publicResponseBeanexceptionHandler(MethodArgumentNotValidExceptione){log.info("reqparamserror",e);Stringmessage=e.getBindingResult().getFieldError().getDefaultMessage();if(StringUtils.isNotBlank(message)&&!"不能為空".equals(message)){returnResponseBean.error(ApiCode.PARAM_INVALID.getValue(),message);}returnResponseBean.error(ApiCode.PARAM_INVALID.getValue(),ApiCode.PARAM_INVALID.getMessage());}@ExceptionHandler(value=TokenErrorException.class)@ResponseBodypublicResponseBeantokenErrorExceptionHandler(TokenErrorExceptione){log.info("登錄失效:{}",e.getMessage(),e);returnResponseBean.error(ApiCode.SERVICE_ERROR.getValue(),"登錄已失效,請重新登錄！");}@ExceptionHandler(value=ServiceException.class)@ResponseBodypublicResponseBeanbusinessExceptionHandler(ServiceExceptione){log.info("serviceerror:{}",e.getMessage(),e);returnResponseBean.error(ApiCode.SERVICE_ERROR.getValue(),e.getMessage());}}publicenumErrorCodeEnumimplementsEnumBase{FAIL(-1,"網絡異常，請稍後再試"),SUCCESS(0,"請求成功"),MAX_UPLOAD_SIZE_ERROR(1000,"上傳文件不能超過20M"),SERVICE_BUSY_ERROR(1000,"服務器正在繁忙，請稍後再試哦~"),REQUEST_PARAMS_FAIL(1001,"參數錯誤"),USER_NOT_LOGIN(1002,"用戶未登錄，請重新登錄"),USER_HAS_EXIST_LOGIN(1007,"用戶已經存在，請檢查！"),USER_CODE_NOT_EXIST(1008,"用戶編碼不存在，請檢查！"),REQUEST_PARAMS_FORMAT_ERROR(1102,"請求參數格式異常"),PASSWORD_SAFETY_ERROE(2204,"密碼不符合安全規則，請通過忘記密碼重新設置8-18位數字+字母組合密碼"),TOKEN_EXPIRED(2301,"token過期"),TOKEN_ERROR(2302,"token驗證失敗"),INTERFACE_ERROR(10000,"接口服務器異常");privatefinalintcode;privatefinalStringmsg;ErrorCodeEnum(intcode,Stringmsg){this.code=code;this.msg=msg;}@OverridepublicintgetCode(){returnthis.code;}@OverridepublicStringgetMsg(){returnthis.msg;}}
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