SpringCloud教程 | 四.服务消费者(Feign)

太过爱你忘了你带给我的痛 2021-09-26 11:04 455阅读 0赞

**前言**

**简介**

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，并和Eureka结合，默认实现了负载均衡的效果。

## 实战 ##

### 一.环境准备 ###

1.启动服务注册中心：spring-cloud-eureka

2.启动服务提供方：spring-cloud-eureka-client【端口为2001】

3.修改spring-cloud-eureka-client中配置的端口号server.port(需与2中不一样)，在2的基础上再次启动【端口为2002】

详情如下：[SpringCloud教程 | 一.服务的注册与发现（Eureka）][SpringCloud_ _ _._Eureka]

### 二.建立服务消费者 ###

1.新建项目：spring-cloud-eureka-feign

pom.xml

<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.9.RELEASE</version>
    		<relativePath/> 
    	</parent>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    		<java.version>1.8</java.version>
    		<spring-cloud.version>Edgware.SR1</spring-cloud.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-eureka</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-feign</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-tomcat</artifactId>
    			<scope>provided</scope>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>${spring-cloud.version}</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>

2.application.properties

eureka.client.serviceUrl.defaultZone=http://localhost:1001/eureka
    server.port=8000
    spring.application.name=eureka-feign

3.在启动类上用@EnableFeignClients注解开启Feign的功能

package com.gwd;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.netflix.feign.EnableFeignClients;
    
    @SpringBootApplication
    @EnableDiscoveryClient
    @EnableFeignClients
    public class SpringCloudEurekaFeignApplication {
    	public static void main(String[] args) {
    		SpringApplication.run(SpringCloudEurekaFeignApplication.class, args);
    	}
    }

4.创建服务TestService

【注意】这里的@FeignClient("eureka-client")是服务提供方的spring.application.name，这与ribbon有所区别

package com.gwd.feign;
    
    import org.springframework.cloud.netflix.feign.FeignClient;
    import org.springframework.web.bind.annotation.RequestMapping;
    /** 
    * @FileName TestService.java
    * @Description:TODO
    * @author JackHisen(gu.weidong)
    * @version V1.0
    * @createtime 2018年1月22日 上午10:29:54 
    * 修改历史：
    * 时间           作者          版本        描述
    *====================================================  
    */
    @FeignClient("eureka-client")
    public interface TestService {
    	@RequestMapping("/dc")
    	public String testFeign();
    }

5.创建Controller:TestFeignController

package com.gwd.controller;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import com.gwd.feign.TestService;
    
    /** 
    * @FileName TestFeignController.java
    * @Description:TODO
    * @author JackHisen(gu.weidong)
    * @version V1.0
    * @createtime 2018年1月22日 上午10:32:52 
    * 修改历史：
    * 时间           作者          版本        描述
    *====================================================  
    */
    @RestController
    public class TestFeignController {
    	@Autowired
    	private TestService testService;
    	@RequestMapping("/feign")
    	public String testFeignController() {
    		return testService.testFeign();
    	}
    }

6.请求后结果显示：

![SouthEast][]

![SouthEast 1][]

[SpringCloud_ _ _._Eureka]: http://blog.csdn.net/gwd1154978352/article/details/79077976
[SouthEast]: /images/20210923/0a167323647f434ebf2e3b4186d4ff5a.png
[SouthEast 1]: /images/20210923/b65d9cbbaa2544c2b61b8b163eb3ca9b.png