spring cloud 2.x版本 Feign服務發現教程(內含集成Hystrix熔斷機制)

時間 2019-11-06

標籤 spring cloud 2.x 版本 feign 服務發現教程內含集成 hystrix 熔斷機制欄目 Spring 简体版

原文原文鏈接

前言

本文采用Spring cloud本文爲2.1.8RELEASE，version=Greenwich.SR3 java

本文基於前兩篇文章eureka-server和eureka-client的實現。參考git

eureka-servergithub

eureka-clientweb

建立Feign工程

1.1 建立sping boot工程：eureka-feign

1.2 添加pom.xml相關依賴

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
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1.3 application添加配置信息

spring:
 application:
 name: eureka-feign

server:
 port: 8601

eureka:
 instance:
 hostname: localhost
 lease-renewal-interval-in-seconds: 5
 lease-expiration-duration-in-seconds: 10
 client:
 service-url:
 defaultZone: http://eureka1.server.com:8701/eureka/,http://eureka2.server.com:8702/eureka/,http://eureka3.server.com:8703/eureka/
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1.4 啓動類EurekaFeignApplication增長註解

package spring.cloud.demo.eurekafeign;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableDiscoveryClient
@EnableFeignClients
@SpringBootApplication
public class EurekaFeignApplication {

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

}
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@EnableDiscoveryClient:這裏使用EnableDiscoveryClient註解，在eureka-client已說明，這邊就不在闡述spring

@EnableFeignClients:啓用Feign客戶端瀏覽器

1.5 建立服務接口EurekaFeignService

package spring.cloud.demo.eurekafeign.service;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;

/** * @auther: maomao * @DateT: 2019-09-17 */
@FeignClient(value = "eureka-client")
public interface EurekaFeignService {

    @RequestMapping(value = "/info")
    String syaHello();
}
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@FeignClient:定義Feign客戶端，調用遠程client。eureka-client表明client的spring.application.name,調用遠程地址示例：http://eureka-client/info網絡

1.6 建立EurekaFeignController控制類

package spring.cloud.demo.eurekafeign.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import spring.cloud.demo.eurekafeign.service.EurekaFeignService;

import javax.annotation.Resource;

/** * @auther: maomao * @DateT: 2019-09-17 */
@RestController
@RequestMapping("/feign")
public class EurekaFeignController {

    @Resource
    private EurekaFeignService eurekaFeignService;

    @RequestMapping("/sayHello")
    public String sayHello() {
        return "feign result: " + eurekaFeignService.syaHello();
    }

}
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1.7 啓動eureka-feign服務

能夠在eureka-server服務註冊中心看到eureka-feign是否註冊成功。app

紅框中內容表明eureka-feign已經正常啓動併成功註冊到eureka-server服務註冊中心。負載均衡

訪問http://localhost:8601/feign/sayHello，顯示以下：分佈式

多刷新幾回能夠在瀏覽器中看到不通的結果，端口是變化的。

Feign默認的負載均衡策略是輪詢方式。若是想修改Feign的負載均衡策略請參考eureka-ribbon中的配置

至此，一個簡單的單機Feign服務消費者工程就搭建完成了。

彩蛋

Feign集成Hystrix熔斷機制

pom.xml增長依賴

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
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增長application.yml配置

feign:
 hystrix:
 enabled: true
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修改EurekaFeignService

在@FeignClient註解中增長fallback

package spring.cloud.demo.eurekafeign.service;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;

/** * @auther: maomao * @DateT: 2019-09-17 */
@FeignClient(value = "eureka-client", fallback = EurekaFeignServiceFailure.class)
public interface EurekaFeignService {

    @RequestMapping(value = "/info")
    String syaHello();
}
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增長EurekaFeignServiceFailure類：

package spring.cloud.demo.eurekafeign.service;

import org.springframework.stereotype.Service;

/** * @auther: maomao * @DateT: 2019-09-17 */
@Service
public class EurekaFeignServiceFailure implements EurekaFeignService {
    @Override
    public String syaHello() {
        return "網絡繁忙，請稍後在試";
    }
}
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