spring cloud 2.x版本 Feign服务发现教程(内含集成Hystrix熔断机制)

时间 2019-11-06

标签 spring cloud 2.x 版本 feign 服务发现教程内含集成 hystrix 熔断机制栏目 Spring 繁體版

原文原文链接

前言

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

本文基于前两篇文章eureka-server和eureka-client的实现。参考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相关依赖

<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>
复制代码

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/
复制代码

1.4 启动类EurekaFeignApplication增长注解

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);
    }

}
复制代码

@EnableDiscoveryClient:这里使用EnableDiscoveryClient注解，在eureka-client已说明，这边就不在阐述spring

@EnableFeignClients:启用Feign客户端浏览器

1.5 建立服务接口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();
}
复制代码

@FeignClient:定义Feign客户端，调用远程client。eureka-client表明client的spring.application.name,调用远程地址示例：http://eureka-client/info网络

1.6 建立EurekaFeignController控制类

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();
    }

}
复制代码

1.7 启动eureka-feign服务

能够在eureka-server服务注册中心看到eureka-feign是否注册成功。app

红框中内容表明eureka-feign已经正常启动并成功注册到eureka-server服务注册中心。负载均衡

访问http://localhost:8601/feign/sayHello，显示以下：分布式

多刷新几回能够在浏览器中看到不通的结果，端口是变化的。

Feign默认的负载均衡策略是轮询方式。若是想修改Feign的负载均衡策略请参考eureka-ribbon中的配置

至此，一个简单的单机Feign服务消费者工程就搭建完成了。

彩蛋

Feign集成Hystrix熔断机制

pom.xml增长依赖

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

增长application.yml配置

feign:
 hystrix:
 enabled: true
复制代码

修改EurekaFeignService

在@FeignClient注解中增长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();
}
复制代码

增长EurekaFeignServiceFailure类：

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 "网络繁忙，请稍后在试";
    }
}
复制代码

启动eureka-feign服务

首先在eureka-client全不启动的状况，访问http://localhost:8601/feign/sayHello看是否全不正常，而后停掉其中一个eureka-client，在屡次刷新http://localhost:8601/feign/sayHello,显示以下：

说明增长的Hystrix已经生效。

至此，Feign集成Hystrix熔断机制所有完成。

总结

本文主要简单实现了feign做为服务消费的简单应用和Hystrix的集成。

代码地址

gitHub地址

《Srping Cloud 2.X小白教程》目录

转载请注明出处，

联系方式：4272231@163.com