Feign Client相比Rest Template可以自動實現(xiàn)負載均衡，而且接口使用也更加友好，但是一般情況下Feign Client都需要依賴eureka吭狡。其實我們也可以在沒有eureka的環(huán)境下，直接使用Feign Client以故。既用到了Feign Client的好處，又為將來切換到Spring Cloud做好預(yù)備.

添加依賴

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
    <version>2.1.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    <version>2.1.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>com.netflix.archaius</groupId>
    <artifactId>archaius-core</artifactId>
    <version>0.7.6</version>
</dependency>
<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.5</version>
</dependency>
<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>27.1-jre</version>
</dependency>

定義Feign接口

• HomeApi

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

@FeignClient(value = "home", path = "/home")
public interface HomeApi {
    @GetMapping("/ping")
    String ping();
}

注意：這里的value = "home"需要與后面配置文件中的home一致

配置文件

• application.yml

eureka:
  client:
    enabled: false

home:
  ribbon:
    listOfServers: http://localhost:8081

上面配置文件中home interface的目標地址是http://localhost:8081裆操，如果有多個的話怒详，可以使用逗號（,）隔開

接口調(diào)用

• FeignWithoutEurekaApplication

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;

import javax.annotation.Resource;

@EnableFeignClients
@SpringBootApplication
public class FeignWithoutEurekaApplication implements ApplicationRunner {

    @Resource
    private HomeApi homeApi;

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

    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println(homeApi.ping());
    }
}

注意需要添加注解@EnableFeignClients

執(zhí)行結(jié)果

標準輸出中輸出

success

參考

• 基于Eureka的遠程調(diào)用 - Feign Client