电商项目专题(五)-通用的的异常处理

1.场景预设

1.1.场景

加入我们做新增商品，需要接收下面的参数：

price：价格 name：名称

然后对数据做简单校验：

价格不能为空

新增时，自动生成 ID ，然后随商品对象一起返回

1.2.代码实现

项目结构：

实体类：

packagecom.yigou.item.pojo;importlombok.AllArgsConstructor;importlombok.Data;importlombok.NoArgsConstructor;/** * @author bruceliu * @create 2019-09-01 12:36 * @description */@Data@NoArgsConstructor@AllArgsConstructorpublicclassItem{privateInteger id;privateString name;privateLong price;}

service：

packagecom.yigou.item.service;importcom.yigou.item.pojo.Item;importorg.springframework.stereotype.Service;importjava.util.Random;/** * @author bruceliu * @create 2019-09-03 22:12 * @description */@ServicepublicclassItemService{publicItemsaveItem(Item item){// 商品新增intid=newRandom().nextInt(100);item.setId(id);returnitem;}}

controller：

packagecom.yigou.item.controller;importcom.yigou.item.pojo.Item;importjava.util.List;importcom.yigou.item.service.ItemService;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.http.HttpStatus;importorg.springframework.http.ResponseEntity;importorg.springframework.web.bind.annotation.PostMapping;importorg.springframework.web.bind.annotation.RequestMapping;importorg.springframework.web.bind.annotation.RestController;/** * @author bruceliu * @create 2019-09-01 12:38 * @description */@RestController@RequestMapping("item")publicclassItemController{@AutowiredprivateItemService itemService;@PostMappingpublicResponseEntity<Item>saveItem(Item item){// 校验商品的价格if(item.getPrice()==null){returnResponseEntity.status(HttpStatus.BAD_REQUEST).body(null);}Item item1=itemService.saveItem(item);returnResponseEntity.status(HttpStatus.CREATED).body(item1);}}

测试：

如果price为空：

改写Controller给出异常消息：

packagecom.yigou.item.controller;importcom.yigou.item.pojo.Item;importjava.util.List;importcom.yigou.item.service.ItemService;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.http.HttpStatus;importorg.springframework.http.ResponseEntity;importorg.springframework.web.bind.annotation.PostMapping;importorg.springframework.web.bind.annotation.RequestMapping;importorg.springframework.web.bind.annotation.RestController;/** * @author bruceliu * @create 2019-09-01 12:38 * @description */@RestController@RequestMapping("item")publicclassItemController{@AutowiredprivateItemService itemService;@PostMappingpublicResponseEntity<Item>saveItem(Item item){// 校验商品的价格if(item.getPrice()==null){thrownewRuntimeException("价格不能为空！");}Item item1=itemService.saveItem(item);returnResponseEntity.status(HttpStatus.CREATED).body(item1);}}

测试结果：

是SpringMvc处理的异常，但是500是服务器内部错误，而真正异常的原因是客户端引发的异常
上述异常是由 SpringMVC 处理的，而我们真正要的是自己处理！

2.通用的异常处理

放到yigou-common里面公共起来

ExceptionEnum：枚举 异常

packagecom.yigou.common.enums;importlombok.*;/** * @author bruceliu * @create 2019-09-03 22:35 * @description */@Getter@NoArgsConstructor@AllArgsConstructorpublicenumExceptionEnum{PRICE_CANNOT_BE_NULL(400,"价格不能为空！");privateintcode;privateString msg;}

ExceptionResult：异常结果 定义

packagecom.yigou.common.vo;importcom.yigou.common.enums.ExceptionEnum;importlombok.Data;/** * @author bruceliu * @create 2019-09-03 22:37 * @description */@DatapublicclassExceptionResult{privateintstatus;privateString message;privateLong timestamp;publicExceptionResult(ExceptionEnum em){this.status=em.getCode();this.message=em.getMsg();this.timestamp=System.currentTimeMillis();}}

YigouException：自定义 异常

packagecom.yigou.common.exception;importcom.yigou.common.enums.ExceptionEnum;importlombok.AllArgsConstructor;importlombok.Getter;importlombok.NoArgsConstructor;/** * @author bruceliu * @create 2019-09-03 22:40 * @description */@NoArgsConstructor@AllArgsConstructor@GetterpublicclassYigouExceptionextendsRuntimeException{privateExceptionEnum exceptionEnum;}

CommonExceptionHandler：定义 通用的异常处理
添加依赖（不需要指定版本）

<dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId></dependency>

packagecom.yigou.common.advice;importcom.yigou.common.exception.YigouException;importcom.yigou.common.vo.ExceptionResult;importorg.springframework.http.ResponseEntity;importorg.springframework.web.bind.annotation.ControllerAdvice;importorg.springframework.web.bind.annotation.ExceptionHandler;/** * @author bruceliu * @create 2019-09-03 22:41 * @description */@ControllerAdvicepublicclassCommonExceptionHandler{@ExceptionHandler(YigouException.class)publicResponseEntity<ExceptionResult>handleException(YigouException e){returnResponseEntity.status(e.getExceptionEnum().getCode()).body(newExceptionResult(e.getExceptionEnum()));}}

在yigou-item-service里面依赖yigou-common：

<dependency><groupId>com.yigou.parent</groupId><artifactId>yigou-common</artifactId><version>1.0-SNAPSHOT</version></dependency>

改写 ItemController

packagecom.yigou.item.controller;importcom.yigou.common.enums.ExceptionEnum;importcom.yigou.common.exception.YigouException;importcom.yigou.item.pojo.Item;importjava.util.List;importcom.yigou.item.service.ItemService;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.http.HttpStatus;importorg.springframework.http.ResponseEntity;importorg.springframework.web.bind.annotation.PostMapping;importorg.springframework.web.bind.annotation.RequestMapping;importorg.springframework.web.bind.annotation.RestController;/** * @author bruceliu * @create 2019-09-01 12:38 * @description */@RestController@RequestMapping("item")publicclassItemController{@AutowiredprivateItemService itemService;@PostMappingpublicResponseEntity<Item>saveItem(Item item){// 校验商品的价格if(item.getPrice()==null){thrownewYigouException(ExceptionEnum.PRICE_CANNOT_BE_NULL);}Item item1=itemService.saveItem(item);returnResponseEntity.status(HttpStatus.CREATED).body(item1);}}

测试：