前言:

必需学会SpringBoot基础知识

简介:

spring cloud 为开发人员提供了快速构建分布式系统的一些工具，包括配置管理、服务发现、断路器、路由、微代理、事件总线、全局锁、决策竞选、分布式会话等等。它运行环境简单，可以在开发人员的电脑上跑。

工具:

JDK8

apache-maven-3.5.2

IntelliJ IDEA 2017.3 x64

文章 SpringCloud 教程 第一篇: 服务的注册与发现（Eureka） 介绍了服务注册与发现，其中服务注册中心Eureka Server，是一个实例，当成千上万个服务向它注册的时候，它的负载是非常高的，这在生产环境上是不太合适的，这篇文章主要介绍怎么将Eureka Server集群化。

一、准备工作

创建三个实例:

1. eureka-server-peer1
2. eureka-server-peer2
3. eureka-server-peer3

二、Code.View

2.0 peer*

<?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.lwc</groupId><artifactId>eureka-server-peer1</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>eureka-server-peer1</name><description>Demo project for Spring Boot</description><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.10.RELEASE</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>Edgware.SR3</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><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></project>

2.1 peer1

package com.lwc;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;/*** @author Eddie*/
@EnableEurekaServer
@SpringBootApplication
public class EurekaServerPeer1Application {public static void main(String[] args) {SpringApplication.run(EurekaServerPeer1Application.class, args);}
}

server:port: 8861
spring:application:name: eureka-server-peer1profiles:active: peer1
eureka:instance:hostname: eureka-server-peer1client:registerWithEureka: falsefetchRegistry: falseserviceUrl:defaultZone: http://eureka-server-peer2:8862/eureka/,http://eureka-server-peer3:8863/eureka/

2.2 peer2

package com.lwc;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;/*** @author Eddie*/
@EnableEurekaServer
@SpringBootApplication
public class EurekaServerPeer2Application {public static void main(String[] args) {SpringApplication.run(EurekaServerPeer2Application.class, args);}
}

server:port: 8862
spring:application:name: eureka-server-peer2profiles:active: peer2
eureka:instance:hostname: eureka-server-peer2client:registerWithEureka: falsefetchRegistry: falseserviceUrl:defaultZone: http://eureka-server-peer2:8861/eureka/,http://eureka-server-peer3:8863/eureka/

2.3 peer3

package com.lwc;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;/*** @author Eddie*/
@EnableEurekaServer
@SpringBootApplication
public class EurekaServerPeer3Application {public static void main(String[] args) {SpringApplication.run(EurekaServerPeer3Application.class, args);}
}

server:port: 8863
spring:application:name: eureka-server-peer3profiles:active: peer3
eureka:instance:hostname: eureka-server-peer3client:registerWithEureka: falsefetchRegistry: falseserviceUrl:defaultZone: http://eureka-server-peer2:8862/eureka/,http://eureka-server-peer3:8861/eureka/

2.4 改造 eureka-client

package com.lwc.controller;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.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;/*** @author eddie.lee* @Package com.lwc.controller* @ClassName EurekaClientController* @description* @date created in 2018-03-26 17:19* @modified by*/
@RestController
@RequestMapping("/eureka")
public class EurekaClientController {@Autowiredprivate DiscoveryClient discoveryClient;@GetMapping("/client")public String home(@RequestParam String name) {List<Map<String, Object>> list = new ArrayList<>();Map<String, Object> map = new HashMap<>(16);List<String> stringList = discoveryClient.getServices();stringList.forEach(str -> {List<ServiceInstance> serviceInstances = discoveryClient.getInstances(str);serviceInstances.forEach(ins -> {map.put("host", ins.getHost());map.put("port", ins.getPort());map.put("serviceId", ins.getServiceId());map.put("uri", ins.getUri());list.add(map);});});String url = null;for (Map<String, Object> m : list) {for (String k : m.keySet()) {System.out.println(k + " : " + m.get(k));url = "欢迎点击:  "+m.get("uri") + "/eureka/client?name=" + name;}}return url;}}

eureka:client:serviceUrl:#defaultZone: http://localhost:8761/eureka/defaultZone: http://eureka-server-peer1:8861/eureka/
server:port: 8762

三、测试

启动:

访问: http://localhost:8861/

最后改造 client 是为了让大家学习一下获取信息,访问:  http://localhost:8762/eureka/client?name=eddie

欢迎点击: http://EDDIE-THINKPAD:8762/eureka/client?name=eddie

题外话:

也可以通过原来第一篇的项目结构, 修改配置文件的端口达到效果;

1. 通过Maven打包之后

2. CMD下运行:

java -jar eureka-server-0.0.1-SNAPSHOT.jar - -spring.profiles.active=peer1

java -jar eureka-server-0.0.1-SNAPSHOT.jar - -spring.profiles.active=peer2

3. 在运行:

java -jar eureka-client-0.0.1-SNAPSHOT.jar

技巧:

eureka.instance.preferIpAddress=true是通过设置ip让eureka让其他服务注册它。也许能通过去改变去通过改变host的方式。

原理:

peer1 8861,peer2 8862,peer2 8863 相互感应，当有服务注册时，两个Eureka-server是对等的，它们都存有相同的信息，这就是通过服务器的冗余来增加可靠性，当有一台服务器宕机了，服务并不会终止，因为另一台服务存有相同的数据。

三、源码下载

标签 10-1

https://github.com/eddie-code/SpringCloudDemo