场景预设
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
代码
实体类
:
package com.leyou.item.pojo;
import lombok.Data;
@Data
public class Item {
private Integer id;
private String name;
private Long price;
}
service
:
package com.leyou.item.service;
import com.leyou.item.pojo.Item;
import org.springframework.stereotype.Service;
import java.util.Random;
@Service
public class ItemService {
public Item saveItem(Item item){
// 商品新增
int id = new Random().nextInt(100);
item.setId(id);
return item;
}
}
controller
:
package com.leyou.item.web;
import com.leyou.item.pojo.Item;
import com.leyou.item.service.ItemService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("item")
public class ItemController {
@Autowired
private ItemService itemService;
@PostMapping
public ResponseEntity<Item> saveItem(Item item){
// 校验商品的价格
if (item.getPrice() == null){
return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(null);
}
Item item1 = itemService.saveItem(item);
return ResponseEntity.status(HttpStatus.CREATED).body(item1);
}
}
测试:
改写:
上述异常是由 SpringMVC 处理的,而我们真正要的是自己处理!
通用的异常处理 —— 放到 ly-common
里面
ExceptionEnum
:枚举 异常
package com.leyou.common.enums;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
@Getter
@NoArgsConstructor
@AllArgsConstructor
public enum ExceptionEnum {
PRICE_CANNOT_BE_NULL(400, "价格不能为空!")
;
private int code;
private String msg;
}
ExceptionResult
:异常结果 定义
package com.leyou.common.vo;
import com.leyou.common.enums.ExceptionEnum;
import lombok.Data;
@Data
public class ExceptionResult {
private int status;
private String message;
private Long timestamp;
public ExceptionResult(ExceptionEnum em) {
this.status = em.getCode();
this.message = em.getMsg();
this.timestamp = System.currentTimeMillis();
}
}
LyException
:自定义 异常
package com.leyou.common.exception;
import com.leyou.common.enums.ExceptionEnum;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
@NoArgsConstructor
@AllArgsConstructor
@Getter
public class LyException extends RuntimeException {
private ExceptionEnum 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>
package com.leyou.common.advice;
import com.leyou.common.exception.LyException;
import com.leyou.common.vo.ExceptionResult;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
@ControllerAdvice
public class CommonExceptionHandler {
@ExceptionHandler(LyException.class)
public ResponseEntity<ExceptionResult> handleException(LyException e){
return ResponseEntity.status(e.getExceptionEnum().getCode())
.body(new ExceptionResult(e.getExceptionEnum()));
}
}
在 ly-item-service
里面依赖 ly-common
:
<dependency>
<groupId>com.leyou.common</groupId>
<artifactId>ly-common</artifactId>
<version>1.0.0-SNAPSHOT</version>
</dependency>
改写 ItemController
package com.leyou.item.web;
import com.leyou.common.enums.ExceptionEnum;
import com.leyou.common.exception.LyException;
import com.leyou.item.pojo.Item;
import com.leyou.item.service.ItemService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("item")
public class ItemController {
@Autowired
private ItemService itemService;
@PostMapping
public ResponseEntity<Item> saveItem(Item item){
// 校验商品的价格
if (item.getPrice() == null){
throw new LyException(ExceptionEnum.PRICE_CANNOT_BE_NULL);
}
Item item1 = itemService.saveItem(item);
return ResponseEntity.status(HttpStatus.CREATED).body(item1);
}
}
测试: