eureka服务调用，接上文的服务注册（使用OpenFeign进行服务调用），接我的一篇eureka注册文章继续创作。链接：https://blog.csdn.net/weixin_48421942/article/details/123163198

1. 新建消费者model，开启eureka服务注册中心，将对应的服务注册进去，然后消费者model调用服务中心注册的服务提供者的服务

2. 我上文中的服务提供者，只是注册了，并没有对应的服务提供，现在下面得加入对应的服务。

3. openfeign是springcloud在feign的基础上支持springmvc的注解，如@RequestMapping等等。openfeign的@feignclient可以解析springmvc的@requestMapping注解下的接口，并通过动态代理的方式产生实现类，实现类中做负载均衡并调用其他服务。

4. 在eureka8001模块加入controller包，加入控制层代码：
   项目结构如下：
   
   

controller代码如下：

package com.cloud.eureka8001.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {


    @RequestMapping(value = "/get",method = {RequestMethod.GET})
    public String hello(){
        return "hello eureka";
    }

}

5. 添加好需要调用的服务后，新建消费者80模块，我结构和我上图一样，上图是建好的项目结构。80模块对应的pom文件代码，yml配置代码如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         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">
    <parent>
        <artifactId>cloud-zjie</artifactId>
        <groupId>com.cloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>eureka80-consumer</artifactId>

    <dependencies>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

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

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>


</project>

server:
  port: 80
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://localhost:7001/eureka/
spring:
  application:
    name: Ribbion-consumer80

启动类代码（重要）
启动类要加新注解和服务注册，服务提供不一样，注解：@EnableDiscoveryClient 是开启服务发现客户端，顾名思义就是服务调用
@EnableFeignClients 启用openfeign服务调用功能
代码如下：

package com.cloud.eureka80;

import com.cloud.eureka80.rules.MySelfRules;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class Eurekaconsumer80 {

    public static void main(String[] args) {
        SpringApplication.run(Eurekaconsumer80.class,args);
    }

}

创建server层用接口，进行restful api调用，代码如下：

package com.cloud.eureka80.service;


import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;

@Component
@FeignClient(value = "PROVIDENCE-8001")
public interface TestService {

    @GetMapping("/get")
    public String hello();
}

最后新建controller层对这个接口进行调用，代码如下：

package com.cloud.eureka80.controller;


import com.cloud.eureka80.service.TestService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;

@RestController
@Slf4j
public class TestController {


    @Autowired
    private TestService testService;


    @GetMapping("/consumer/get")
    public String get(){
        log.info("用户正在使用消费者端口");
        return testService.hello();
    }


}

最后实现结果：

总结

• 服务提供者8001，新建restful api接口提供服务，注册到eureka中心
• 服务消费者80，导入openfeign依赖，启动类加上@EnableDiscoveryClient
  @EnableFeignClients注解，标记这是一个服务消费者模块
• 建立service层利用接口和注解@FeignClient(value = “PROVIDENCE-8001”)这里的value中的值，就说服务提供者8001的spring application name 上篇文章编写的，这里的意思是调用这个PROVIDENCE-8001中的接口，通过restful api接口地址进行调用
• 最后建一个controller进行调用就行了