SpringCloud Alibaba微服务实战(三) - Nacos服务创建消费者(Feign)

什么是Feign

Feign 是一个声明式的伪 Http 客户端，它使得写 Http 客户端变得更简单。使用 Feign，只需要创建一个接口并注解。它具有可插拔的注解特性，可使用 Feign 注解和 JAX-RS 注解。Feign 支持可插拔的编码器和解码器。Feign 默认集成了 Ribbon，Nacos 也很好的兼容了 Feign，默认实现了负载均衡的效果

Feign 采用的是基于接口的注解Feign 整合了 ribbon

创建服务者注册，请参考文章：SpringCloud Alibaba微服务实战(二) - Nacos服务注册与发现

构建服务消费者cloud-consumer-feign进行服务调用

1.在父项目中创建子module项目名字为cloud-consumer-feign，在pom中引入nacos服务注册依赖

<!--Spring web--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!--SpringCloud Alibaba nacos--> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency>

完整服务消费者cloud-consumer-feign的pom.xml

<?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-alibaba</artifactId> <groupId>com.zsy.springcloud</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>cloud-consumer-feign</artifactId> <dependencies> <!--Spring web--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!--SpringCloud Alibaba nacos--> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> <repositories> <!--指定阿里云镜像库下载依赖--> <repository> <id>central</id> <name>aliyunmaven</name> <url>http://maven.aliyun.com/nexus/content/groups/public/</url> </repository> </repositories> </project>

2.配置application.yml或者properties文件

server: port: 8083 spring: #服务应用名字 application: name: cloud-consumer-feign cloud: # 指定nacos控制台地址,配置注册ip:端口，注意即使是80端口也不可能省略 nacos: discovery: server-addr: 127.0.0.1:8848

3.FeignClient接口定义AccountService

package com.zsy.springcloud.service; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import java.util.Map; @FeignClient("cloud-account") public interface AccountService { //获取客户信息 @RequestMapping(value = "/getAccount", method = RequestMethod.GET) public Map<String,Object> getAccount(); }

4.创建消费者AccountConsumerController

package com.zsy.springcloud.controller; import com.zsy.springcloud.service.AccountService; import lombok.extern.log4j.Log4j2; 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.RestController; import org.springframework.web.client.RestTemplate; import javax.annotation.Resource; import java.util.HashMap; import java.util.Map; @Log4j2 @RestController public class AccountConsumerController { @Resource private AccountService accountService; @RequestMapping(value = "/getAccount", method = RequestMethod.GET) public Map<String,Object> getAccount() { Map<String,Object> account = new HashMap<>(); log.info("---------消费者开始------------"); account = accountService.getAccount(); log.info("---------消费者结束--------account{}----", account); return account; } }

5.配置消费者启动服务的启动类

package com.zsy.springcloud; 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 //开启服务注册 @EnableFeignClients//开启feign客户端 public class FeignConsumerApplication { public static void main(String [] args) { SpringApplication.run(FeignConsumerApplication.class, args); } }

6.启动cloud-consumer服务项目，启动成功，如下图 7. 验证服务，浏览器访问http://localhost:8083/getAccount，返回如下图 查看消费者cloud-consumer控制台，如下图 查看服务者cloud-account控制台，如下图 码云地址：https://gitee.com/zlzhaoe/cloud-alibaba