Spring Cloud系列教程三 ：声明式服务调用Spring Cloud Fegin（F版）

Feign集成了Ribbon，让客户端具有负载均衡的能力，同时简化了开发

github地址：https://github.com/erlieStar/spring-cloud-learning

1.项目配置如下

pom.xml

    org.springframework.cloud
    spring-cloud-starter-netflix-eureka-client


    org.springframework.cloud
    spring-cloud-starter-openfeign

application.yaml

server:
  port: 9001

spring:
  application:
    name: consumer-feign

eureka:
  client:
    service-url:
      defaultZone: http://localhost:7001/eureka

2.启动类加上@EnableFeignClients注解开启Feign的功能

3.定义接口，通过@FeignClient(服务名)来指定调用哪个服务

@RestController
@EnableEurekaClient
@EnableFeignClients
@SpringBootApplication
public class ConsumerFeign {

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

    @Autowired
    private SimpleClient simpleClient;

    @FeignClient(value = "producer-simple")
    public interface SimpleClient {
        @RequestMapping("hello")
        String hello(@RequestParam String name);
    }

    @RequestMapping("hello")
    public String hello(@RequestParam String name) {
        return simpleClient.hello(name);
    }
}

启动eureka-service（spring-cloud-eureka）

接着启动2个producer-simple（spring-cloud-ribbon）

初始端口为8001，启动一个实例后，修改端口为8002，再启动一个实例

访问http://localhost:9001/hello?name=xiaoshi

交替显示

hello xiaoshi, I am from port: 8001
hello xiaoshi, I am from port: 8002

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参考博客

[1]https://www.fangzhipeng.com/springcloud/2018/08/03/sc-f3-feign.html