1. 新建 cloud-consumer-feign-order80

2. pom.xml

http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
cloud2020 com.atguigu.springcloud 1.0-SNAPSHOT
4.0.0

<artifactId>cloud-consumer-feign-order80</artifactId>

<dependencies>  
    <!--openfeign-->  
    <dependency>  
        <groupId>org.springframework.cloud</groupId>  
        <artifactId>spring-cloud-starter-openfeign</artifactId>  
    </dependency>  
    <!--eureka client-->  
    <dependency>  
        <groupId>org.springframework.cloud</groupId>  
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>  
    </dependency>  
    <!--引入自定义的api通用包，可以使用Payment支付Entity-->  
    <dependency>  
        <groupId>com.atguigu.springcloud</groupId>  
        <artifactId>cloud-api-commons</artifactId>  
        <version>${project.version}</version>  
    </dependency>  
    <!--web-->  
    <dependency>  
        <groupId>org.springframework.boot</groupId>  
        <artifactId>spring-boot-starter-web</artifactId>  
    </dependency>  
    <dependency>  
        <groupId>org.springframework.boot</groupId>  
        <artifactId>spring-boot-starter-actuator</artifactId>  
    </dependency>  
    <!--一般基础通用配置-->  
    <dependency>  
        <groupId>org.springframework.boot</groupId>  
        <artifactId>spring-boot-devtools</artifactId>  
        <scope>runtime</scope>  
        <optional>true</optional>  
    </dependency>  
    <dependency>  
        <groupId>org.projectlombok</groupId>  
        <artifactId>lombok</artifactId>  
        <optional>true</optional>  
    </dependency>  
    <dependency>  
        <groupId>org.springframework.boot</groupId>  
        <artifactId>spring-boot-starter-test</artifactId>  
        <scope>test</scope>  
    </dependency>  
</dependencies>  

3. application.yml

server:
port: 80

eureka:
client:
register-with-eureka: false
service-url:
defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka

4. 主启动类

package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;
@SpringBootApplication
@EnableFeignClients //开启Feign
public class OrderFeignMain80 {

public static void main(String\[\] args) {  
    SpringApplication.run(OrderFeignMain80.class,args);  
}  

}

5. 业务类

//业务逻辑接口 + @FeignClient 配置调用provider服务
package com.atguigu.springcloud.service;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
@Component
@FeignClient(value = "CLOUD-PROVIDER-SERVICE") //指定调用哪个微服务
public interface PaymentFeignService {

@GetMapping(value = "/payment/get/{id}")    //哪个地址  
CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);  

}

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package com.atguigu.springcloud.controller;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import com.atguigu.springcloud.service.PaymentFeignService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
@Slf4j
public class OrderFeignController {
@Resource
private PaymentFeignService paymentFeignService;

@GetMapping(value = "/consumer/payment/get/{id}")  
public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id){  
    return paymentFeignService.getPaymentById(id);  
}  

}

6. 测试

先启动2个eureka集群 7001/7002
在启动2个微服务 8001/8002
启动OpenFeign 80

多次刷新，8001和8002会依次出现，Feign自带负载均衡配置项

总结：

客户端服务接口根据 @FeigClient所显示的微服务名称去调用 服务暴露对外提供的方法。