SpringCloud 第二篇：服务提供者 (eureka client)

浅浅的花香味﹌ 2022-05-24 06:34 235阅读 0赞

在上一篇中我创建了一个注册中心，现在我就可以给他注册服务。当client向server注册时，它会提供一些元数据，例如主机和端口，URL，主页等。Eureka server 从每个client实例接收心跳消息。 如果心跳超时，则通常将该实例从注册server中删除。

## 1.创建服务 ##

创建服务的过程和创建注册中心的步骤一样，可以参考[SpringCloud 第一篇： 服务注册中心（Eureka）][SpringCloud _ _Eureka]。

创建完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">
    	<modelVersion>4.0.0</modelVersion>
    
    	<groupId>com.example</groupId>
    	<artifactId>demo</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>demo</name>
    	<description>Demo project for Spring Boot</description>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.2.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>Finchley.BUILD-SNAPSHOT</spring-cloud.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</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>
    
    	<repositories>
    		<repository>
    			<id>spring-snapshots</id>
    			<name>Spring Snapshots</name>
    			<url>https://repo.spring.io/snapshot</url>
    			<snapshots>
    				<enabled>true</enabled>
    			</snapshots>
    		</repository>
    		<repository>
    			<id>spring-milestones</id>
    			<name>Spring Milestones</name>
    			<url>https://repo.spring.io/milestone</url>
    			<snapshots>
    				<enabled>false</enabled>
    			</snapshots>
    		</repository>
    	</repositories>
    
    
    </project>

## 2.添加服务注解 ##

通过注解@EnableEurekaClient 表明自己是一个eurekaclient。

package com.example.client;
    
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @SpringBootApplication
    @EnableEurekaClient
    @RestController
    public class DemoClientApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(DemoClientApplication.class, args);
    	}
    
    	@Value("${server.port}")
    	String port;
    	@RequestMapping("/hello")
    	public String home(@RequestParam String name) {
    		return "hello 来自 port:" +port +"的，" + name;
    	}
    }

## 3.配置文件 ##

在配置文件中配置服务注册中心的地址，applicaton.yml配置如下：

eureka:
      client:
        serviceUrl:
          #注册中心地址
          defaultZone: http://localhost:10000/eureka/
    server:
      port: 10001
    spring:
      application:
        #服务名用于将来服务之间的调用（注意：服务名中含有下划线将无法使用Feign进行跨服务调用）
        name: service-demo

## 4.发现服务 ##

启动工程，打开[http://localhost:10000/][http_localhost_10000]，即eureka server 的网址，可以看到已经注册了一个服务，服务名为：service-demo。

![70][]

## 5.调用服务 ##

这时打开 [http://localhost:10001/hello?name=yanling][http_localhost_10001_hello_name_yanling] ，你会在浏览器上看到 :

![70 1][]

[SpringCloud _ _Eureka]: https://blog.csdn.net/qq_34996727/article/details/80405053
[http_localhost_10000]: http://localhost:10000/
[70]: /images/20220524/c02db6d46dea46c58e6ae8a48ebb579a.png
[http_localhost_10001_hello_name_yanling]: http://localhost:10001/hello?name=yanling
[70 1]: /images/20220524/1b18dfa690604d71ba3a7c09edeaf8e8.png