第二篇：SpringCloud 服务的注册与发现Eureka（Dalston.SR5版本）

一.创建父工程

1 首先创建一个maven父工程。

<?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.zhihua</groupId><artifactId>spring_cloud_pro</artifactId><version>0.0.1-SNAPSHOT</version><packaging>pom</packaging><name>spring_cloud_pro</name><description>Demo project for Spring Boot</description><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><java.version>1.8</java.version></properties><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.13.RELEASE</version></parent><dependencyManagement><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>Dalston.SR5</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></project>

二 . 创建Eureka Server

2 然后创建2个子工程工程: 一个model工程作为服务注册中心，即Eureka Server,另一个作为Eureka Client。

下面以创建Eureka Server为例子，详细说明创建过程：

右键工程->创建model-> 选择spring initialir 如下图：

创建完后的工程，其pom.xml继承了父pom文件，同时父工程加入相应的model，引入依赖，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"><modelVersion>4.0.0</modelVersion><groupId>com.zhihua</groupId><artifactId>eureka_server</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>eureka_server</name><description>Demo project for Spring Boot</description><parent><groupId>com.zhihua</groupId><artifactId>spring_cloud_pro</artifactId><version>0.0.1-SNAPSHOT</version><relativePath/> <!-- lookup parent from repository --></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.RELEASE</spring-cloud.version></properties><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-eureka-server</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build>**重点内容**
</project>

3 启动一个服务注册中心

    只需要一个注解@EnableEurekaServer，这个注解需要在springboot工程的启动application类上加：

@SpringBootApplication
@EnableEurekaServer    //eureka服务
public class EurekaServerApplication {public static void main(String[] args) {SpringApplication.run(EurekaServerApplication.class, args);}
}

4 配置文件appication.yml

spring:application:name: eureka-server      #服务名称
server:port: 8761                     #端口号
eureka:client:register-with-eureka: false   #eureka服务自身也是个客户端  此处因为是单机版关闭fetch-registry: false          #同上service-url:defaultZone: http://localhost:8761/eureka       #服务端默认地址

5 eureka server 启动工程,打开浏览器访问：
http://localhost:8761 ,界面如下：

三、创建一个服务提供者 (eureka client)

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。
此处同样是通过jpa查询数据库，具体代码参照上一章节
userControlle类：

package com.zhihua.eureka_client.controller;import com.netflix.appinfo.InstanceInfo;
import com.netflix.discovery.EurekaClient;
import com.zhihua.eureka_client.entity.User;
import com.zhihua.eureka_client.jpa.UserJpa;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.*;@RestController
public class userController {@Autowiredprivate UserJpa userJpa;@Autowiredprivate EurekaClient eurekaClient;@Autowiredprivate DiscoveryClient discoveryClient;@GetMapping("/simple/{id}")public User findById(@PathVariable Long id){User user = userJpa.getOne(id);return user;}@PostMapping(value = "/user")public User postUser(@RequestBody User user){return user;}@GetMapping(value = "/getUser")public User getUser(User user){return user;}@GetMapping("/eureka-instance")public String serviceUrl() {InstanceInfo instance = this.eurekaClient.getNextServerFromEureka("EUREKA-SERVER", false);return instance.getHomePageUrl();}@GetMapping("/instance-info")public ServiceInstance showInfo() {ServiceInstance localServiceInstance = this.discoveryClient.getLocalServiceInstance();return localServiceInstance;}}

创建过程同server类似,创建完pom.xml如下：

<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></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-actuator</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-eureka</artifactId></dependency></dependencies>

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

@SpringBootApplication
@EnableEurekaClient
public class EurekaClientApplication {public static void main(String[] args) {SpringApplication.run(EurekaClientApplication.class, args);}
}

配置文件appication.yml

server:port: 9060
spring:application:name: eureka-clientdatasource:driver-class-name: com.mysql.jdbc.Driverurl: jdbc:mysql://localhost/test?characterEncoding=utf8username: rootpassword: 123456jpa:properties:hibernate:show_sql: trueformat_sql: true
eureka:instance:hostname: localhostprefer-ip-address: trueclient:healthcheck:enabled: trueservice-url:defaultZone: http://${eureka.instance.hostname}:8761/eureka/

启动工程，打开http://localhost:8761 ，即eureka server 的网址

你会发现一个服务已经注册在服务中了，服务名为SERVICE-HI ,端口为9060

此时的项目：