7、sentinel

控制台访问地址：http://localhost:8080/
在这里插入图片描述

依赖

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

配置文件

spring:cloud:sentinel:transport:dashboard: localhost:8080# 不用等到第一次发送请求，就可以连接到控制台eager: true
feign:sentinel:# 开启兜底返回 @FeignClient(value = "ms2", fallback = Ms2FeignFallBack.class)enabled: true

流量控制

比如QPS=1,1s只能处理一个请求，其余请求会走异常处理方法(直接失败的情况下)，也可以设置其他请求排队。

对controller方法流控

/*** 处理controller接口的被限流后的异常处理操作*/
@Component
public class MyBlockExceptionHandler implements BlockExceptionHandler {@Overridepublic void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception {response.setContentType("application/json;charset=utf-8");Map<String, Object> map = new LinkedHashMap<>();map.put("code", 500);map.put("msg", "sentinel限流：" + e.getClass());String string = new ObjectMapper().writeValueAsString(map);PrintWriter writer = response.getWriter();writer.write(string);writer.flush();writer.close();}
}

对@SentinelResource(value = “sm”, blockHandler = “smFallBack”)修饰的方法流控

public String smFallBack(String uuid, BlockException blockException) {return uuid + blockException.getClass();
}

对feign方法流控

Ms2Feign

@FeignClient(value = "ms2", fallback = Ms2FeignFallBack.class)
public interface Ms2Feign {
}

Ms2FeignFallBack

@Component
public class Ms2FeignFallBack implements Ms2Feign {@Overridepublic String aa() {return "aa的兜底回调函数";}@Overridepublic String bb(String name, int age) {return null;}@Overridepublic String cc(String name, int age) {return null;}@Overridepublic String dd(FeignEntity feignEntity) {return null;}@Overridepublic String ee(Map<String, Object> reqMap) {return null;}@Overridepublic String ff(String auth, Map<String, Object> reqMap) {return null;}
}