sentinel官方使用文档：Sentinel · alibaba/spring-cloud-alibaba Wiki · GitHub

引入依赖

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

下载sentinel控制台

下载对应版本的sentinel.jar Releases · alibaba/Sentinel · GitHub

运行jar

java -jar .\sentinel-dashboard-1.6.3.jar

如若8080端口冲突，可使用 -Dserver.port=新端口 进行设置。 

配置控制台信息

application.yml

spring:
  cloud:
    sentinel:
      transport:
        port: 8719  #默认
        dashboard: localhost:8080

控制台显示

第一次发送请求显示

流控规则简单使用

新增流控规则

 超出请求频率

实时监控配置

pom添加依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

application.yml 添加配置

management.endpoints.web.exposure.include=*

 自定义流控响应

添加配置

package com.hdb.pingmoweb.seckill.config;

import com.alibaba.csp.sentinel.adapter.servlet.callback.UrlBlockHandler;
import com.alibaba.csp.sentinel.adapter.servlet.callback.WebCallbackManager;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.fastjson.JSON;
import com.hdb.pingmoweb.common.utils.R;
import org.springframework.context.annotation.Configuration;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Configuration
public class SentinelConfig {

    public SentinelConfig() {
        WebCallbackManager.setUrlBlockHandler(new UrlBlockHandler() {
            @Override
            public void blocked(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws IOException {
                R error = R.error("请求流量过大");
                httpServletResponse.setCharacterEncoding("UTF-8");
                httpServletResponse.setContentType("application/json");
                httpServletResponse.getWriter().write(JSON.toJSONString(error));
            }
        });
    }
}

测试返回 

Feign 远程调用熔断

配置文件打开 Sentinel 对 Feign 的支持：

feign.sentinel.enabled=true

创建feign失败回调类，返回熔断后数据，保证其他服务能正常运行。

package com.hdb.pingmoweb.seckill.feign.fallback;

import com.hdb.pingmoweb.common.utils.R;
import com.hdb.pingmoweb.seckill.feign.ProductFeignService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import java.util.Map;

@Slf4j
@Component
public class ProductFeignServiceFallBack implements ProductFeignService {
    @Override
    public R list(Map<String, Object> params) {
        log.info("熔断方法调用...list");
        return R.error("太多请求");
    }
}

 feign服务接口配置熔断回调类

package com.hdb.pingmoweb.seckill.feign;

import com.hdb.pingmoweb.common.utils.R;
import com.hdb.pingmoweb.seckill.feign.fallback.ProductFeignServiceFallBack;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.Map;

@FeignClient(name = "pingmoweb-product", fallback = ProductFeignServiceFallBack.class)
public interface ProductFeignService {

    @RequestMapping("/product/brand/list")
    public R list(@RequestParam Map<String, Object> params);

}

调用方手动指定远程降级策略触发熔断机制，返回熔断数据

提供方手动指定远程降级策略，返回的是默认降级数据（限流数据）（提供方配置降级相当于全局降级）