SpringCloud項(xiàng)目集成Feign、Hystrix過程解析

[root@node01 cloud]# tree weather/
weather/
├── Application.java  #主程序啟動(dòng)入口
├── controller
│  ├── CityController.java  #控制路由,比如訪問127.0.0.1:8080/cities, 這里調(diào)用cityClient方法
└── service
  └── CityClient.java    #具體方法的實(shí)現(xiàn),這里就具體實(shí)現(xiàn)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; #引入熔斷器
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;  #讓eureka能發(fā)現(xiàn)自己
import org.springframework.cloud.netflix.feign.EnableFeignClients;   #引入feign

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients  #聲明這個(gè)程序引入FeignClient
@EnableCircuitBreaker #聲明這個(gè)程序引入熔斷器
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,比如訪問127.0.0.1:8080/cities
    @HystrixCommand(fallbackMethod="defaultCities") #給另外一個(gè)服務(wù)設(shè)置hystrix熔斷器,并聲明fallbackMethod(回調(diào)方法)假如另外一個(gè)服務(wù)掛了,就調(diào)用defaultCities方法
    public String listCity() {
        // 通過Feign客戶端來查找
        String body = cityClient.listCity();  #調(diào)用service里CityClient.java的cityClient方法,獲取城市數(shù)據(jù)
        return body;              #返回,訪問127.0.0.1:8080/cities就能返回城市數(shù)據(jù)
    }

    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服務(wù)注冊(cè)到eureka的ID,通過這個(gè)ID就能訪問到msa-weather-city微服務(wù)
public interface CityClient {

    @GetMapping("/cities")  #調(diào)用msa-weather-city微服務(wù)里的/cities接口
    String listCity();    #調(diào)用msa-weather-city微服務(wù)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