springcloud实战之6 服务消费者（Feign）

川长思鸟来 2022-06-03 01:28 220阅读 0赞

上一篇介绍了 [springboot实战之服务消费者（ribbon）][springboot_ribbon] 消费服务，本篇介绍利用Feign消费服务。

## 简介 ##

Feign是一个声明式的伪Http客户端，它使得写Http客户端变得更简单。使用Feign，只需要创建一个接口并注解。它具有可插拔的注解特性，可使用Feign 注解和JAX-RS注解。Feign支持可插拔的编码器和解码器。Feign默认集成了Ribbon，并和Eureka结合，默认实现了负载均衡的效果。

## 创建服务消费者（springcloud-consumer-feign） ##

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath />
    </parent>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

## 添加入口类（SpringCloudConsumerFeignApplication.java） ##

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

## 添加配置文件（application.yml） ##

server:
      port: 8003
    spring:
      application:
        name: springcloud-consumer-feign
    eureka:
      client:
        service-url:
          defaultZone: http://peer1:8080/eureka/

## 新建service层接口 ##

定义一个feign接口，通过@FeignClient（“服务名”），来指定调用哪个服务。

@FeignClient(value = "springcloud-producer-rest")
    public interface ISchedualRestService { 
        @GetMapping("/api/rest/info")
        String info() ;
    }

## 新建web层接口 ##

对外暴露http接口

@RestController
    @RequestMapping("/api/rest")
    public class RestfulController { 
    
        @Autowired private ISchedualRestService iSchedualRestService ;
    
        @GetMapping(value = "/getMessage")
        public String getMessage(){
            return iSchedualRestService.info() ;
        }
    }

## 启动项目 ##

1.启动springcloud-eureka-server集群，端口分别为 8080，8090

2.启动springcloud-producer-rest，端口分别为 8001

3.启动服务消费者springcloud-consumer-feign。端口 8003

访问效果：

![这里写图片描述][SouthEast]

访问服务接口效果

![这里写图片描述][SouthEast 1]

## 参考文档 ##

[spring-cloud-feign][]

## 源码 ##

[springcloud-server-eureka][]

[springcloud-producer-rest][]

[springcloud-consumer-feign][]

## 历史文章 ##

[springcloud实战之高可用服务注册中心（eureka集群）][springcloud_eureka]

[springcloud实战之服务注册与发现（eureka实现）][springcloud_eureka 1]

[springcloud实战之技术选型：dubbo还是springcloud][springcloud_dubbo_springcloud]

[springboot实战之服务消费者（ribbon）][springboot_ribbon]

[springboot_ribbon]: http://blog.csdn.net/u012806787/article/details/78796605
[SouthEast]: /images/20220603/7ac0de23f2dd49cfbf03c1d06c580a71.png
[SouthEast 1]: /images/20220603/a32d8a6462404f5ea4e87c868031345a.png
[spring-cloud-feign]: http://cloud.spring.io/spring-cloud-static/Edgware.RELEASE/multi/multi_spring-cloud-feign.html
[springcloud-server-eureka]: https://github.com/shiyuan2he/springcloud/tree/master/springcloud-server-eureka
[springcloud-producer-rest]: https://github.com/shiyuan2he/springcloud/tree/master/springcloud-producer-rest
[springcloud-consumer-feign]: https://github.com/shiyuan2he/springcloud/tree/master/springcloud-consumer-feign
[springcloud_eureka]: http://blog.csdn.net/u012806787/article/details/78793639
[springcloud_eureka 1]: http://blog.csdn.net/u012806787/article/details/78790958
[springcloud_dubbo_springcloud]: http://blog.csdn.net/u012806787/article/details/78789312