SpringCloud项目集成Feign、Hystrix过程解析

[root@node01 cloud]# tree weather/
weather/
├── Application.java  #主程序启动入口
├── controller
│  ├── CityController.java  #控制路由,比如访问127.0.0.1:8080/cities, 这里调用cityClient方法
└── service
  └── CityClient.java    #具体方法的实现,这里就具体实现cityClient方法(interface)

package com.waylau.spring.cloud.weather;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker; #引入熔断器
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;  #让eureka能发现自己
import org.springframework.cloud.netflix.feign.EnableFeignClients;   #引入feign

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients  #声明这个程序引入FeignClient
@EnableCircuitBreaker #声明这个程序引入熔断器
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

package com.waylau.spring.cloud.weather.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.waylau.spring.cloud.weather.service.CityClient; #引用service/CityClient.java

@RestController
public class CityController {
    @Autowired
    private CityClient cityClient;

    @GetMapping("/cities") #控制路由,比如访问127.0.0.1:8080/cities
    @HystrixCommand(fallbackMethod="defaultCities") #给另外一个服务设置hystrix熔断器,并声明fallbackMethod(回调方法)假如另外一个服务挂了,就调用defaultCities方法
    public String listCity() {
        // 通过Feign客户端来查找
        String body = cityClient.listCity();  #调用service里CityClient.java的cityClient方法,获取城市数据
        return body;              #返回,访问127.0.0.1:8080/cities就能返回城市数据
    }

    public String defaultCities() {        
        return "City Data Server is down!";
    }
}

package com.waylau.spring.cloud.weather.service;

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
@FeignClient("msa-weather-city") #msa-weather-city是msa-weather-city服务注册到eureka的ID,通过这个ID就能访问到msa-weather-city微服务
public interface CityClient {

    @GetMapping("/cities")  #调用msa-weather-city微服务里的/cities接口
    String listCity();    #调用msa-weather-city微服务里的/cities接口里的listCity()方法
}

spring.application.name: micro-weather-eureka-client-feign-hystrix

eureka.client.serviceUrl.defaultZone: http://localhost:8761/eureka/

feign.client.config.feignName.connectTimeout: 5000
feign.client.config.feignName.readTimeout: 5000