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章
目
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通过之前的学习，我们知道可以使用OpenFeign代替Ribbon+RestTemplate实现服务的负载均衡调用，下面我们来准备好演示环境。
第1步：创建Module
我们在mscloud下创建名为cloud-consumer-feign-order80模块
第2步：改pom
pom.xml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>mscloud</artifactId>
<groupId>com.panziye.springcloud</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>cloud-consumer-feign-order80</artifactId>
<dependencies>
<!-- OpenFign -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<!-- eureka client -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<!-- 引入自定义的api通用包，可以使用支付Payment等Entity -->
<dependency>
<groupId>com.panziye.springcloud</groupId>
<artifactId>cloud-api-commons</artifactId>
<version>${project.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
</project>
我们除了Eureka依赖还添加了OpenFeign依赖（如果你的依赖报错，请加入版本号），我们打开依赖查看，发现OpenFeign依赖以及集成了Ribbon
第3步：写yml
application.yml如下：
server:
port: 80
spring:
application:
name: cloud-order-feign-service
eureka:
client:
#表示是否将自己注册进eureka服务中心，默认true
register-with-eureka: false
#表示是否从EurekaServer抓取已有注册信息，默认true。单节点无所谓，集群必须设置true才能配合ribbon使用负载均衡
fetch-registry: true
service-url: #指向eureka集群
defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka,http://eureka7003.com:7003/eureka
第4步：主启动
新建OrderFeignMain80主启动类：
package com.panziye.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;
@SpringBootApplication
@EnableFeignClients
public class OrderFeignMain80 {
public static void main(String[] args) {
SpringApplication.run(OrderFeignMain80.class,args);
}
}
提示：@EnableFeignClients用于激活OpenFeign客户端
第5步：业务类
1）在service包下新建OrderFeignService接口：
注意：这里定义的接口应与服务提供者的service层接口对应，我这里只演示get，另外其返回值与服务提供者的controller对应，这就是我们希望的面向微服务接口编程。
package com.panziye.springcloud.service;
import com.panziye.springcloud.entities.CommonResult;
import com.panziye.springcloud.entities.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
@Component
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface OrderFeignService {
//匹配服务提供者请求Mapping
@GetMapping(value = "/payment/get/{id}")
public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);
}
注意：@FeignClient注解表明此接口使用OpenFeign发请求，value指定服务提供者应用名称，@PathVariable不能丢
2）在controller包下新建OrderFeignController类：
package com.panziye.springcloud.controller;
import com.panziye.springcloud.entities.CommonResult;
import com.panziye.springcloud.entities.Payment;
import com.panziye.springcloud.service.OrderFeignService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
@Slf4j
public class OrderFeignController {
@Resource
private OrderFeignService orderFeignService;
@GetMapping("/consumer/payment/get/{id}")
public CommonResult<Payment> getPayment(@PathVariable("id") Long id){
return orderFeignService.getPaymentById(id);
}
}
第6步：测试
我们先启动7001、7002、7003这3个eureka注册中心，再启动8001和8002这两个服务提供者，最后启动我们新建的OrderFeignMain80，访问http://localhost/consumer/payment/get/1测试，发现正常访问，默认使用的是Ribbon的轮询策略。
