11、Feign负载均衡

11.1、简介

11.2、Feign能干什么？

11.3、Feign集成了Ribbon

11.4 springcloud-consumer-dept-feign

创建一个springcloud-consumer-dept-feign空maven的空项目，这也是一个消费者，端口也是80，只是这个消费者使用Feign实现的负载均衡

pom.xml

<dependencies>
    <!--feign-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-feign</artifactId>
        <version>1.4.7.RELEASE</version>
    </dependency>
    <!--Ribbon-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-ribbon</artifactId>
        <version>1.4.7.RELEASE</version>
    </dependency>
    <!--导入Ribbon的同时要导入erueka，因为它要发现服务从那里来-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka</artifactId>
        <version>1.4.7.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>com.wu</groupId>
        <artifactId>springcloud-api</artifactId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!--热部署工具-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
    </dependency>
</dependencies>

application.yml

和springcloud-consumer-dept-80项目的一摸一样

修改springcloud-api

添加依赖 <!--feign--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-feign</artifactId> <version>1.4.7.RELEASE</version> </dependency> 从前面了解到，Feign是通过注解接口，而Ribbon是通过微服务名字，那么下面给springcloud-api添加一个service包

并写上几个注解 @Component //Feign客户端的服务名 @FeignClient(value = "SPRINGCLOUD-PROVIDER-DEPT") public interface DeptClientService { @GetMapping("/dept/get/{id}") Dept queryById(@PathVariable("id") Long id); @PostMapping("/dept/add") boolean addDept(Dept dept); @RequestMapping("/dept/list") List<Dept> queryAll(); }

然后在springcloud-consumer-dept-feign项目的controller也要做相应的修改

DeptConsumerController

@Controller
public class DeptConsumerController {
          
   
	
    //这里直接把springcloud-api的DeptClientService接口注入进来
    @Autowired
    private DeptClientService deptClientService = null;
	//然后通过接口来调用方法，调用方法后，它会调用上面类对应的方法，最后调用其服务名字的接口
    @RequestMapping("/consumer/dept/get/{id}")
    @ResponseBody
    public Dept queryById(@PathVariable("id") Long id) {
          
   
        return this.deptClientService.queryById(id);
    }

    @RequestMapping("/consumer/dept/add")
    @ResponseBody
    public boolean add(Dept dept) {
          
   
        return this.deptClientService.addDept(dept);
    }

    @RequestMapping("/consumer/dept/list")
    @ResponseBody
    public List<Dept> queryAll() {
          
   
        return this.deptClientService.queryAll();
    }

}

最后还要在启动类上添加FeignClient注解

FeignDeptConsumer_80

@SpringBootApplication
@EnableFeignClients(basePackages = {
          
   "com.wu.springcloud"})
public class FeignDeptConsumer_80 {
          
   
    public static void main(String[] args) {
          
   
        SpringApplication.run(FeignDeptConsumer_80.class, args);
    }
}

最后启动7001、… 、8001、… 、feign的80项目，测试