<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>

hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 1000
      circuitBreaker:
        requestVolumeThreshold: 3

package com.inspur.scdemo.client;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
@EnableCircuitBreaker
public class ClientApplication {
    public static void main(String[] args) {
        SpringApplication.run(ClientApplication.class, args);
    }
}

package com.inspur.scdemo.client.controller;

import com.netflix.hystrix.contrib.javanica.annotation.DefaultProperties;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/hystrix")
/**defaultFallback为默认的降级方法，没有参数，返回值要与Hystrix方法的返回值相同*/
@DefaultProperties(commandProperties = {
    @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "3"),
    @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "2000"),
}, defaultFallback = "defaulFallback")
public class HystrixController {
    private Logger logger = LoggerFactory.getLogger(HystrixController.class);

    @RequestMapping("/test")
    /**fallbackMethod为降级方法，需要与Hystrix方法的签名和返回值一致*/
    @HystrixCommand(
        commandProperties = {
            @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "3"),
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "3000"),
        },
        fallbackMethod = "fallback")
    public String test(long id) {
        logger.info(id + "");

        try {
            Thread.sleep(1000 * 5);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "test";
    }

    @RequestMapping("/test2")
    @HystrixCommand()
    public String test2(long id) {
        logger.info(id + "");

        try {
            Thread.sleep(1000 * 5);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "test2";
    }

    public String fallback(long id) {
        logger.info(id + "");
        return "fallback";
    }

    public String defaulFallback() {
        return "defaulFallback";
    }
}

feign:
  hystrix:
    enabled: true

package com.inspur.scdemo.client.feign;

import com.inspur.scdemo.client.entity.CallResult;
import com.inspur.scdemo.client.entity.User;
import com.inspur.scdemo.client.feign.fallback.UserFallBack;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestParam;

//scdemo-server为服务名称
@FeignClient(name = "scdemo-server", fallback = UserFallBack.class)
public interface IUserFeign {
    @PostMapping("/user/addUser")
    CallResult<User> addUser(@RequestBody User user);

    @PostMapping("/user/getUser")
    CallResult<User> getUser(@RequestParam("id") long id);
}

package com.inspur.scdemo.client.feign.fallback;

import com.inspur.scdemo.client.entity.CallResult;
import com.inspur.scdemo.client.entity.User;
import com.inspur.scdemo.client.feign.IUserFeign;
import org.springframework.stereotype.Component;

@Component
public class UserFallBack implements IUserFeign {
    @Override
    public CallResult<User> addUser(User user) {
        return new CallResult<>(1, "增加用户服务暂不可用！");
    }

    @Override
    public CallResult<User> getUser(long id) {
        return new CallResult<>(1, "获取用户服务暂不可用！");
    }
}

package com.inspur.scdemo.client.controller;

import com.inspur.scdemo.client.entity.CallResult;
import com.inspur.scdemo.client.entity.User;
import com.inspur.scdemo.client.feign.IUserFeign;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/userfeign")
public class FeignController {
    private Logger logger = LoggerFactory.getLogger(FeignController.class);
    @Autowired
    private IUserFeign userFeign;

    @RequestMapping("/addUser")
    public CallResult<User> addUser(String name, String address) {
        logger.info("name={},address={}", name, address);
        CallResult<User> result = new CallResult<>();
        try {
            User user = new User();
            user.setName(name);
            user.setAddress(address);
            CallResult<User> resultServer = userFeign.addUser(user);
            logger.info("server返回结果：{}" + resultServer);

            User user2 = resultServer.getResult();
            user2.setName("client-" + user2.getName());
            result.setResult(user2);
        } catch (Exception e) {
            result = new CallResult<User>(-1, "发生异常");
            e.printStackTrace();
        }
        return result;
    }

    @RequestMapping("/getUser")
    public CallResult<User> getUser(long id) {
        logger.info(id + "");

        CallResult<User> result = null;
        try {
            result = userFeign.getUser(id);
        } catch (Exception e) {
            result = new CallResult<User>(-1, "发生异常");
            e.printStackTrace();
        }
        return result;
    }
}

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>

package com.inspur.scdemo.gateway.controller;

import com.inspur.scdemo.gateway.entity.CallResult;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FallbackController {
    @RequestMapping("/fallback")
    public CallResult<String> fallback() {
        return new CallResult<>(-10, "服务不可用");
    }
}

spring:
  cloud:
    gateway:
      discovery:
        locator:
          enabled: false #是否开启服务注册和发现功能；将为每一个服务创建一个router，这个router把以服务名开头的请求路径转发到对应的服务上
          lower-case-service-id: true #将请求路径上的服务名转为小写
      routes:
      - id: client
        uri: lb://scdemo-client
        predicates:
        - Path=/scdemo-client/**
        filters:
        - StripPrefix=1 #路由时会去除/scdemo-client
        - name: Hystrix
          args:
            name: fallbackcmd
            fallbackUri: forward:/fallback

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
</dependency>

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

management:
  endpoints:
    web:
      exposure:
        include: hystrix.stream