前言
Feign的中文名称翻译过来是伪装
那么Feign伪装的是什么呢?答案很明确,Feign伪装的是服务提供者。
Feign可以用来做什么?既然能伪装,当然能提供服务提供者的功能,即RPC调用服务提供者功能。
一、构建Feign
step1
新建一个SpringBoot项目,导入web,feign,eureka client的pom依赖;这种依赖在各种IDE及SpringBoot构建网页上都是直接输入关键字按Enter就可以的
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step2 配置application.yml文件,还是用前两篇的Eureka server
eureka: client: serviceUrl: defaultZone: http://server1:20001/eureka/server: port: 8766spring: application: name: service-feign
step3
配置负载均衡策略,新建一个类,配置bean Irule就可以了
import com.netflix.loadbalancer.IRule;import com.netflix.loadbalancer.RandomRule;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class LoadBalancerConfig { @Bean public IRule getRule() { return new RandomRule(); }}
step4
主类开启Feign注解@EnableFeignClients,即允许开启Feign
import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;import org.springframework.cloud.openfeign.EnableFeignClients;@EnableEurekaClient@EnableFeignClients@SpringBootApplicationpublic class FeignApplication { public static void main(String[] args) { SpringApplication.run(FeignApplication.class, args); }}
step5
关键步骤来了,创建一个伪服务提供者接口(不需要实现),你伪装谁@FeignClient的value就写谁的名字。调用哪个接口就在RequestMapping 的value标注那个接口的url,方法名随便起,参数要给人间传过去
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(value = "service-hi")public interface ServiceFeign { @RequestMapping(value = "/hi", method = RequestMethod.GET) String sayHi(@RequestParam(value = "name") String name);}
step6
创建一个Controller便于前端观察
@RestControllerpublic class FeignController { @Autowired private ServiceFeign serviceFeign; @GetMapping(value = "/hi") public String sayHi(@RequestParam String name) { return serviceFeign.sayHi(name); }}
step7
启动eureka server,启动三个service-hi,启动service-feign,点击service-feign
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step8 输入url,多次刷新,发现确实是按照负载均衡的随机策略来的
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总结
本篇git地址https://github.com/KouLouYiMaSi/springcloud