sentinel上下文配置（玩转Sentinel定义异常-整合Open-Feign）

默认降级返回数据问题

• 限流和熔断返回的数据有问题
• 微服务交互基本都是json格式，如果让⾃定义异常信息

AlibabCloud版本升级，不兼容问题

• v2.1.0到v2.2.0后，Sentinel⾥⾯依赖进⾏了改动，且不向下兼容

⾃定义降级返回数据

• 【旧版】实现UrlBlockHandler并且重写blocked⽅法

@Component public class XdclassUrlBlockHandler implements UrlBlockHandler { @Override public void blocked(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws IOException { //降级业务处理 } }

• 【新版】实现BlockExceptionHandler并且重写handle⽅法

public class XdclassUrlBlockHandler implements BlockExceptionHandler { @Override public void handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws Exception { //降级业务处理 } }

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

【新版】实现BlockExceptionHandler并且重写handle⽅法

@Component public class AlibabaUrlBlockHandler implements BlockExceptionHandler { @Override public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception { Map<String,Object> result = new HashMap<>(); if (e instanceof FlowException){ result.put("code",-1); result.put("message","限流异常！"); } else if (e instanceof DegradeException){ result.put("code",-2); result.put("message","降级异常！"); } else if (e instanceof ParamFlowException){ result.put("code",-3); result.put("message","热点异常！"); } else if (e instanceof SystemBlockException){ result.put("code",-4); result.put("message","系统规则异常！"); } else if (e instanceof AuthorityException){ result.put("code",-5); result.put("message","认证异常！"); } //设置返回数据 response.setStatus(200); response.setHeader("content-type","application/json;charset=UTF-8"); response.getWriter().write(JSON.toJSONString(result)); } }

降级测试

流控测试

• 加⼊依赖

<dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId> </dependency>

• 开启Feign对Sentinel的⽀持

#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 public class VideoServiceFallback implements VideoService { @Override public Video findById(int videoId) { Video video = new Video(); video.setTitle("系统默认数据！"); return video; } @Override public int save(Video video) { return 0; } }

• 配置feign容错类

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

• 测试

参考源码：alibaba-cloud: alibaba-cloud学习

参考原文：cyz