新建 spring-cloud-eureka-feign-client Module

pom

<parent>

    <artifactId>spring-cloud-parent</artifactId>

    <groupId>com.karonda</groupId>

    <version>1.0.0</version>

</parent>

<modelVersion>4.0.0</modelVersion>

<artifactId>spring-cloud-eureka-feign-client</artifactId>

<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-web</artifactId>

    </dependency>

    <dependency>

        <groupId>org.springframework.cloud</groupId>

        <artifactId>spring-cloud-starter-openfeign</artifactId>

    </dependency>

</dependencies>

<build>

    <plugins>

        <plugin>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-maven-plugin</artifactId>

        </plugin>

    </plugins>

</build>

application.yml

server:

  port: 8031

eureka:

  client:

    service-url:

      defaultZone: http://localhost:8001/eureka/

spring:

  application:

    name: feign-client

启动类

@EnableFeignClients // 开启 Feign Client

@EnableEurekaClient

@SpringBootApplication

public class EurekaFeignClientApp {

    public static void main(String[] args){

        SpringApplication.run(EurekaFeignClientApp.class, args);

    }

}

FeignClient

@FeignClient("eureka-client")

public interface EurekaClientFeign {

    @GetMapping("/hi")

    String sayHi(@RequestParam(value = "name") String name);

}

Controller

@RestController

public class FeignController {

    @Autowired

    EurekaClientFeign eurekaClientFeign;

    @GetMapping("/hi")

    public String sayHi(@RequestParam String name){

        return eurekaClientFeign.sayHi(name);

    }

}

测试

1. 启动 eureka-server
2. 启动 eureka-client (两个实例：一个 8011 端口，一个 8012 端口)
3. 启动 eureka-feign-client

多次访问 http://localhost:8031/hi?name=victor 可以看到 8011 和 8012 端口交替出现

添加失败重试

添加配置

@Configuration

public class FeignConfig {

    @Bean

    public Retryer feignRetryer(){

        return new Retryer.Default(100, SECONDS.toMillis(1), 5);

    }

}

修改 FeignClient

@FeignClient(value = "eureka-client", configuration = FeignConfig.class)

public interface EurekaClientFeign {

    @GetMapping("/hi")

    String sayHi(@RequestParam(value = "name") String name);

}

使用 HttpClient 或 OkHttp

在 Feign 中，Client 是一个非常重要的组件，Feign 最终发送 Request 请求以及接收 Response 响应都是由 Client 组件完成的。Client 在 Feign 源码中是一个接口，在默认的情况下， Client 的实现类是 Client.Default, Client.Default 是由 HttpURLConnnection 来实现网络请求的。Client 还支持 HttpClient 和 OkhHttp 来进行网络请求

直接添加 HttpClient 或 OkhHttp 依赖包，Feign 会自动使用对应的网络请求框架

完整代码：GitHub

本人 C# 转 Java 的 newbie, 如有错误或不足欢迎指正，谢谢