第十一章 Sentinel⾃定 义异常-整合Open-Feign

异常种类
FlowException //限流异常
DegradeException //降级异常
ParamFlowException //参数限流异常
SystemBlockException //系统负载异常
AuthorityException //授权异常

实现BlockExceptionHandler并且重写handle⽅法

@Component 
public class XdclassUrlBlockHandler implements BlockExceptionHandler {
 @Override
 public void handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws Exception {
     Map backMap=new HashMap<>();
     if (e instanceof FlowException){
         backMap.put("code",-1);
         backMap.put("msg","限流-异常啦");
     }else if (e instanceof DegradeException){
         backMap.put("code",-2);
         backMap.put("msg","降级-异常啦");
     }else if (e instanceof ParamFlowException){
         backMap.put("code",-3);
         backMap.put("msg","热点-异常啦");
     }else if (e instanceof SystemBlockException){
         backMap.put("code",-4);
         backMap.put("msg","系统规则-异常啦");
     }else if (e instanceof AuthorityException){
         backMap.put("code",-5);
         backMap.put("msg","认证-异常啦");
     }
     // 设置返回json数据
     httpServletResponse.setStatus(200);
     httpServletResponse.setHeader("contentType","application/json;charset=UTF-8");

     httpServletResponse.getWriter().write(JSON.toJSONString(backMap));
   }
 }

使⽤Feign整合Sentinel配置
引入依赖

 
   com.alibaba.cloud
   spring-cloud-starter-alibaba-sentinel
  

开启Feign对Sentinel的⽀持

feign:
 sentinel:
  enabled: true

创建容错类, 实现对应的服务接⼝, 记得加注解@Service

@Service
public class VideoServiceFallback implements VideoService {
 @Override
 public Video findById(int videoId) {
     Video video = new Video();
     video.setTitle("熔断降级数据");
     return video;
 }

 @Override
 public int saveVideo(Video video) {
     return 0;
 }
}

配置feign容错类

@FeignClient(name="xdclass-video-service",fallback = VideoServiceFallback.class)