OpenFeign使用步骤

1. 新建 cloud-consumer-feign-order80

 

 2. pom.xml

         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="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

    cloud-consumer-feign-order80

    
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-client
        
        
        
            com.atguigu.springcloud
            cloud-api-commons
            ${project.version}
        
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

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 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 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。