集成Ribbon的客户端调用工具——Feign

  • 2019 年 10 月 6 日
  • 筆記

什么是Feign？

客户端调用工具

  • Ribbon+RestTemplate
  • Feign

Feign特性：

  • Feign本身包含Ribbon
  • Fegin是一个采用基于接口的注解的声明式客户端调用工具，更加简便

基于上个环境来做一些改造：

https://github.com/HCJ-shadow/Ribbon

创建msc-consumer-feign-80工程

pom依赖

主要是spring-cloud-starter-openfeign

<parent>      <groupId>org.springframework.boot</groupId>      <artifactId>spring-boot-starter-parent</artifactId>      <version>2.1.7.RELEASE</version>      <relativePath/> <!-- lookup parent from repository -->  </parent>    <properties>      <java.version>1.8</java.version>      <spring-cloud.version>Greenwich.SR2</spring-cloud.version>  </properties>    <dependencies>      <dependency>          <groupId>org.springframework.cloud</groupId>          <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>      </dependency>      <dependency>          <groupId>org.springframework.boot</groupId>          <artifactId>spring-boot-starter-test</artifactId>          <scope>test</scope>      </dependency>        <dependency>          <groupId>org.springframework.cloud</groupId>          <artifactId>spring-cloud-starter-config</artifactId>      </dependency>      <!--        Eureka客户端启动需要依赖web模块-->      <dependency>          <groupId>org.springframework.boot</groupId>          <artifactId>spring-boot-starter-web</artifactId>      </dependency>        <dependency>          <groupId>org.springframework.cloud</groupId>          <artifactId>spring-cloud-starter-openfeign</artifactId>      </dependency>    </dependencies>    <dependencyManagement>      <dependencies>          <dependency>              <groupId>org.springframework.cloud</groupId>              <artifactId>spring-cloud-dependencies</artifactId>              <version>${spring-cloud.version}</version>              <type>pom</type>              <scope>import</scope>          </dependency>      </dependencies>  </dependencyManagement>    <build>      <plugins>          <plugin>              <groupId>org.springframework.boot</groupId>              <artifactId>spring-boot-maven-plugin</artifactId>          </plugin>      </plugins>  </build>

定义service接口

package zkrun.top.service;    import org.springframework.cloud.openfeign.FeignClient;  import org.springframework.web.bind.annotation.RequestMapping;    @FeignClient("msc-provider")    //@FeignClient("服务名")  public interface FeignService {          @RequestMapping(value = "/info/get")      public String request();    }

定义Controller调用Service接口

package zkrun.top.controller;      import org.springframework.beans.factory.annotation.Autowired;  import org.springframework.web.bind.annotation.RequestMapping;  import org.springframework.web.bind.annotation.RestController;  import zkrun.top.service.FeignService;    @RestController  public class FeignController {        @Autowired      FeignService feignService;        @RequestMapping(value = "/feign/info/get")      public String request()      {         return this.feignService.request();      }    }

主启动类

package zkrun.top;    import org.springframework.boot.SpringApplication;  import org.springframework.boot.autoconfigure.SpringBootApplication;  import org.springframework.cloud.netflix.eureka.EnableEurekaClient;  import org.springframework.cloud.openfeign.EnableFeignClients;    @SpringBootApplication  @EnableFeignClients  @EnableEurekaClient  public class App_Consumer_Feign_80  {     public static void main(String[] args)     {        SpringApplication.run(App_Consumer_Feign_80.class, args);     }  }

application.yaml

server:    port: 80    eureka:    client:      service-url:        defaultZone: http://eureka6001.com:6001/eureka/,http://eureka6002.com:6002/eureka/,http://eureka6003.com:6003/eureka/    spring:    application:      name: feign-consumer

运行测试

集成了轮询效果。

小结：

  • Feign的调用逻辑，访问Controller定义的路径，调用feignService.request()方法，而service接口层中定义了服务名和服务请求路径，最后通过服务名和请求路径实现对服务提供者的调用。
  • Feign的接口在实际开发中经常抽取出一个单独模块，以便复用。

代码参考：https://github.com/HCJ-shadow/Feign

VirMach 便宜 VPS

QNews

QNews