Feign实现负载均衡

Posted 2021-01-10 sakerliu

1.本文在基于Spring Cloud做负载均衡文章上进行开发，网址https://www.cnblogs.com/SakerLiu/p/9743577.html，首先创建一个server，2个端口不同的service，其中server的端口号为8801，service为8802/8803

2.按照创建service的方式新建一个module，命名为my-feigns,修改pom文件server为client，修改application.properties为application.yml，在pom.xml文件中添加如下依赖

<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
　　　　<groupId>org.springframework.boot</groupId>
　　　　<artifactId>spring-boot-starter-web</artifactId>
</dependency>

3.在application.yml添加如下内容

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8801/eureka/
server:
  port: 8811
spring:
  application:
    name: my-feigns

4.在主程序中添加@EnableFeignClients开启注解Feign功能，添加@EnableDiscoveryClient，进行注册，所得代码如下所示

package com.example.myfeigns;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class MyFeignsApplication {

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

5.在该包下新建一个Hello的接口和Controller文件，并加入下述内容

#接口文件
package com.example.myfeigns;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

@FeignClient("my-service")
public interface SayHello {
    @RequestMapping(value = "/hi",method = RequestMethod.GET)
    String sayHi(@RequestParam(value = "name") String name);

}

#Controller文件
package com.example.myfeigns;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @Autowired
    SayHello pp;
    @RequestMapping(value = "/hi",method = RequestMethod.GET)
    public String sayHi(@RequestParam String name){
        return pp.sayHi(name);
    }
}

6.运行主程序，在网页中输入http://localhost:8811/hi?name=lemon，多次刷新发现端口在不断改变。