Eureka 的 Application Service client的注冊以及执行演示样例

【Eureka 的 Application Service client的注冊以及执行演示样例】人生处万类,知识最为贤。这篇文章主要讲述Eureka 的 Application Service client的注冊以及执行演示样例相关的知识，希望能为你提供帮助。
Eureka 服务器架起来了(关于架设步骤參考博客《Linux 下 Eureka 服务器的部署》)，如今怎样把我们要负载均衡的服务器(也就是从 Application Client 接收请求并返回一个响应的 Application Service)注冊到 Eureka？本文以一个演示样例介绍 Eureka Application Service 客户端的 Eureka 生命周期(包含启动时的注冊、侍服演示样例、关闭时的取消注冊)情况。相信读完本文之后，读者能够对 Eureka 的 Application Service 角色有了一个进一步了解，并且全然能够把自己的服务加进 Eureka。
1. Eureka 服务器启动
本文 demo 要求 Eureka Server 已经部署好，并已经启动。关于架设步骤參考博客《Linux 下 Eureka 服务器的部署》。
Eureka 服务器启动以后，能够通过 http://serverIP:8080/eureka/ 或者 http://serverIP:8080/eureka/v2/apps/ 浏览已注冊到 Eureka 的 Application Service。
比方作者在开发环境 PC 訪问服务器端的 http://serverIP:8080/eureka/v2/apps/。页面返回结果例如以下：

< applications> < versions__delta> 1< /versions__delta> < apps__hashcode> UP_1_< /apps__hashcode> < application> < name> EUREKA< /name> < instance> < hostName> localhost.localdomain< /hostName> < app> EUREKA< /app> < ipAddr> 127.0.0.1< /ipAddr> < status> UP< /status> < overriddenstatus> UNKNOWN< /overriddenstatus> < port enabled=" true" > 8080< /port> < securePort enabled=" false" > 443< /securePort> < countryId> 1< /countryId> < dataCenterInfo class=" com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo" > < name> MyOwn< /name> < /dataCenterInfo> < leaseInfo> < renewalIntervalInSecs> 30< /renewalIntervalInSecs> < durationInSecs> 90< /durationInSecs> < registrationTimestamp> 1404789864122< /registrationTimestamp> < lastRenewalTimestamp> 1404798147096< /lastRenewalTimestamp> < evictionTimestamp> 0< /evictionTimestamp> < serviceUpTimestamp> 1404789841811< /serviceUpTimestamp> < /leaseInfo> < metadata class=" java.util.Collections$EmptyMap" /> < appGroupName> UNKNOWN< /appGroupName> < homePageUrl> http://localhost.localdomain:8080/< /homePageUrl> < statusPageUrl> http://localhost.localdomain:8080/Status< /statusPageUrl> < healthCheckUrl> http://localhost.localdomain:8080/healthcheck< /healthCheckUrl> < vipAddress> eureka.mydomain.net< /vipAddress> < isCoordinatingDiscoveryServer> true< /isCoordinatingDiscoveryServer> < lastUpdatedTimestamp> 1404789864122< /lastUpdatedTimestamp> < lastDirtyTimestamp> 1404789841863< /lastDirtyTimestamp> < actionType> ADDED< /actionType> < /instance> < /application> < /applications>

apps__hashcode 是 1，能够看出眼下仅仅有一个 Application Service 注冊到了 Eureka Server，这个名为 Eureka 的 Application Service 仅仅有一个实例，就是这台 Eureka Server 它自己 - localhost.localdomain。为何 Eureka Server 自己也是一个 Application Service 呢？这也是 Eureka 架构健壮性 feature 之中的一个。Eureka Server 之间也会相互注冊，并且还会将注冊到自己的 Application Service 注冊给其它 Eureka Server，避免了一台 Eureka Server 宕机所造成的区域性服务瘫痪。
2. Application Service 配置文件的编写
我们的负载均衡服务器就用官方提供 demo 里的 sampleservice 下的 sample-eureka-service.properties 就可以，当然还要依据实际情况修正一下。比方把 eureka.name 改为我们自己定义的 Application 名以区分开其它服务，把 eureka.port(本服务将会执行并侍服请求的端口)改为我们的 Service 服务器开放的侍服端口 1935，eureka.serviceUrl.default(默认情况下本服务将要注冊到的 Eureka 服务器)：http://serverIP:8080/eureka/v2/：

###Eureka Client configuration for Sample Eureka Service#Properties based configuration for eureka client. The properties specified here is mostly what the users #need to change. All of these can be specified as a java system property with -D option (eg)-Deureka.region=us-east-1 #For additional tuning options refer < url to go here> #Region where eureka is deployed -For AWS specify one of the AWS regions, for other datacenters specify a arbitrary string #indicating the region.This is normally specified as a -D option (eg) -Deureka.region=us-east-1 eureka.region=default#Name of the application to be identified by other serviceseureka.name=sampleservice#Virtual host name by which the clients identifies this service eureka.vipAddress=sampleservice.mydomain.net#The port where the service will be running and serving requests eureka.port=1935#For eureka clients running in eureka server, it needs to connect to servers in other zones eureka.preferSameZone=false#Change this if you want to use a DNS based lookup for determining other eureka servers. For example #of specifying the DNS entries, check the eureka-client-test.properties, eureka-client-prod.properties eureka.shouldUseDns=falseeureka.us-east-1.availabilityZones=defaulteureka.serviceUrl.default=http://serverIP:8080/eureka/v2/

3. 日志配置
就用官方提供 demo 里的 sampleservice 下的 log4j.properties 就可以，当然还要依据实际须要修正一下，比方给 com.defonds.wms.module.server 包的输出级别设置为 DEBUG(log4j.properties 追加 log4j.logger.com.defonds.wms.module.server=DEBUG)。以方便我们研发期跟踪调试。

log4j.rootCategory=INFO,stdout log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%d %-5p %C:%L [%t] [%M] %m%n

4. Application Service 启动时注冊 Eureka
我们希望每台负载均衡服务器在启动时就注冊给 Eureka，以及时承担负载。注冊代码例如以下所看到的：

private static final DynamicPropertyFactory configInstance = com.netflix.config.DynamicPropertyFactory.getInstance(); private static final Logger logger = LoggerFactory.getLogger(SampleEurekaService.class); public void registerWithEureka() { // Register with Eureka DiscoveryManager.getInstance().initComponent( new MyDataCenterInstanceConfig(), new DefaultEurekaClientConfig()); ApplicationInfoManager.getInstance().setInstanceStatus( InstanceStatus.UP); }

第一句载入本地配置文件，initComponent 句依据配置初始化这台 Eureka Application Service。并且注冊到 Eureka Server，setInstanceStatus 句指示本台 Application Service 已启动。准备好侍服网络请求。
5. Application Service 侍服网络请求
Application Service 的 Eureka Server 初始化以及注冊是异步的。须要一段时间。我们想要在确认初始化并注冊成功之后，提供一个 Socket 服务，以供网络请求。demo 须要。这个服务是一次性的，仅仅提供一次 Socket 侍服。
侍服完一次请求后，本 Socket 服务就关闭，并将自己从 Eureka Server 取消注冊。

String vipAddress = configInstance.getStringProperty( " eureka.vipAddress" , " sampleservice.mydomain.net" ).get(); InstanceInfo nextServerInfo = null; while (nextServerInfo == null) { try { nextServerInfo = DiscoveryManager.getInstance() .getDiscoveryClient() .getNextServerFromEureka(vipAddress, false); } catch (Throwable e) { System.out .println(" Waiting for service to register with eureka.." ); try { Thread.sleep(10000); } catch (InterruptedException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }} } System.out.println(" Service started and ready to process requests.." ); try { ServerSocket serverSocket = new ServerSocket(configInstance .getIntProperty(" eureka.port" , 8010).get()); final Socket s = serverSocket.accept(); System.out .println(" Client got connected..Processing request from the client" ); processRequest(s); } catch (IOException e) { e.printStackTrace(); }

Socket 侍服 processRequest 方法具体例如以下：

private void processRequest(final Socket s) { try { BufferedReader rd = new BufferedReader(new InputStreamReader( s.getInputStream())); String line = rd.readLine(); if (line != null) { System.out.println(" Received the request from the client." ); } PrintStream out = new PrintStream(s.getOutputStream()); System.out.println(" Sending the response to the client..." ); out.println(" Reponse at " + new Date()); } catch (Throwable e) { System.err.println(" Error processing requests" ); } finally { if (s != null) { try { s.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }}

6. Application Service 关闭时取消注冊
就像 Spring 管理的对象。初始化、销毁都统一管理起来一样。我们希望本台 Application Service 实例在关闭时也能将自身占用的系统资源释放出来(比方任务列表的线程关闭)，并且取消掉 Eureka 服务器的注冊。

public void unRegisterWithEureka() { // Un register from eureka. DiscoveryManager.getInstance().shutdownComponent(); }

7. 执行 demo
如今我们把完整的 Application Service 整理一下。

/* * Copyright 2012 Netflix, Inc. * *Licensed under the Apache License, Version 2.0 (the " License" ); *you may not use this file except in compliance with the License. *You may obtain a copy of the License at * *http://www.apache.org/licenses/LICENSE-2.0 * *Unless required by applicable law or agreed to in writing, software *distributed under the License is distributed on an " AS IS" BASIS, *WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *See the License for the specific language governing permissions and *limitations under the License. */package com.netflix.eureka; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import java.net.ServerSocket; import java.net.Socket; import java.util.Date; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.netflix.appinfo.ApplicationInfoManager; import com.netflix.appinfo.InstanceInfo; import com.netflix.appinfo.InstanceInfo.InstanceStatus; import com.netflix.appinfo.MyDataCenterInstanceConfig; import com.netflix.config.DynamicPropertyFactory; import com.netflix.discovery.DefaultEurekaClientConfig; import com.netflix.discovery.DiscoveryManager; /** * Sample Eureka service that registers with Eureka to receive and process * requests. * * < p> * This example just receives one request and exits once it receives the request * after processing it. * < /p> * * @author Karthik Ranganathan * */ public class SampleEurekaService { private static final DynamicPropertyFactory configInstance = com.netflix.config.DynamicPropertyFactory .getInstance(); private static final Logger logger = LoggerFactory .getLogger(SampleEurekaService.class); public void registerWithEureka() { // Register with Eureka DiscoveryManager.getInstance().initComponent( new MyDataCenterInstanceConfig(), new DefaultEurekaClientConfig()); ApplicationInfoManager.getInstance().setInstanceStatus( InstanceStatus.UP); String vipAddress = configInstance.getStringProperty( " eureka.vipAddress" , " sampleservice.mydomain.net" ).get(); InstanceInfo nextServerInfo = null; while (nextServerInfo == null) { try { nextServerInfo = DiscoveryManager.getInstance() .getDiscoveryClient() .getNextServerFromEureka(vipAddress, false); } catch (Throwable e) { System.out .println(" Waiting for service to register with eureka.." ); try { Thread.sleep(10000); } catch (InterruptedException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }} } System.out.println(" Service started and ready to process requests.." ); try { ServerSocket serverSocket = new ServerSocket(configInstance .getIntProperty(" eureka.port" , 8010).get()); final Socket s = serverSocket.accept(); System.out .println(" Client got connected..Processing request from the client" ); processRequest(s); } catch (IOException e) { e.printStackTrace(); } this.unRegisterWithEureka(); System.out.println(" Shutting down server.Demo over." ); }public void unRegisterWithEureka() { // Un register from eureka. DiscoveryManager.getInstance().shutdownComponent(); }private void processRequest(final Socket s) { try { BufferedReader rd = new BufferedReader(new InputStreamReader( s.getInputStream())); String line = rd.readLine(); if (line != null) { System.out.println(" Received the request from the client." ); } PrintStream out = new PrintStream(s.getOutputStream()); System.out.println(" Sending the response to the client..." ); out.println(" Reponse at " + new Date()); } catch (Throwable e) { System.err.println(" Error processing requests" ); } finally { if (s != null) { try { s.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }}public static void main(String args[]) { SampleEurekaService sampleEurekaService = new SampleEurekaService(); sampleEurekaService.registerWithEureka(); }}

非常明显我们的 SampleEurekaService 类须要非常多依赖包，这些包都在 eureka-server-1.1.134.war 包里的 WEB-INF/lib 文件夹下，直接拷贝进我们 demo 的 CLASSPATH。不用一个个去找了，还避免了版本号冲突所带来的不必要麻烦。eureka-client-1.1.134.jar 能够去 http://mvnrepository.com/artifact/com.netflix.eureka/eureka-client/1.1.134 下载，或者直接 maven 依赖导入：

< dependency> < groupId> com.netflix.eureka< /groupId> < artifactId> eureka-client< /artifactId> < version> 1.1.134< /version> < /dependency>

类完毕了、环境配置好了。接下来把第二、三步写好的 sample-eureka-service.properties、log4j.properties 也拷贝进 CLASSPATH。接下来就能够执行 demo 了。直接 run SampleEurekaService，发现报下面错误：
2014-07-07 17:01:50,141 WARN com.netflix.config.sources.URLConfigurationSource:120 [main] [< init> ] No URLs will be polled as dynamic configuration sources.
2014-07-07 17:01:50,144 INFO com.netflix.config.sources.URLConfigurationSource:121 [main] [< init> ] To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make config.properties available on classpath.
2014-07-07 17:01:50,178 INFO com.netflix.config.DynamicPropertyFactory:281 [main] [getInstance] DynamicPropertyFactory is initialized with configuration sources: [email protected]
2014-07-07 17:01:58,982 WARN com.netflix.appinfo.PropertiesInstanceConfig:349 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-07 17:02:00,140 WARN com.netflix.discovery.DefaultEurekaClientConfig:95 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-07 17:02:03,559 INFO com.netflix.appinfo.providers.EurekaConfigBasedInstanceInfoProvider:79 [main] [get] Setting initial instance status as: STARTING
Exception in thread " main" java.lang.RuntimeException: Failed to initialize DiscoveryClient!
at com.netflix.discovery.DiscoveryClient.< init> (DiscoveryClient.java:235)
at com.netflix.discovery.DiscoveryClient.< init> (DiscoveryClient.java:169)
at com.netflix.discovery.DiscoveryManager.initComponent(DiscoveryManager.java:84)
at com.netflix.eureka.SampleEurekaService.registerWithEureka(SampleEurekaService.java:60)
at com.netflix.eureka.SampleEurekaService.main(SampleEurekaService.java:139)
Caused by: java.lang.IllegalArgumentException: DiscoveryClient: invalid serviceUrl specified!
at com.netflix.discovery.DiscoveryClient.getEurekaServiceUrlsFromConfig(DiscoveryClient.java:574)
at com.netflix.discovery.DiscoveryClient.getDiscoveryServiceUrls(DiscoveryClient.java:1180)
at com.netflix.discovery.DiscoveryClient.< init> (DiscoveryClient.java:186)
... 4 more
原来 Archaius 不认 sample-eureka-service.properties。没有把我们的配置成功载入。Archaius 的官方说，Archaius 在默认情况下(就是不指定 properties 文件的情况下)会在应用的 classpath 中寻找一个名为 config.properties 的文件并读取其内容作为配置属性。
好吧。我们把 sample-eureka-service.properties 重命名为 config.properties，然后又一次执行 SampleEurekaService。
这次执行成功了，没有再报错。
訪问服务器端的 http://serverIP:8080/eureka/v2/apps/。显演示样例如以下页面信息：

< applications> < versions__delta> 1< /versions__delta> < apps__hashcode> UP_2_< /apps__hashcode> < application> < name> SAMPLESERVICE< /name> < instance> < hostName> defonds-win7< /hostName> < app> SAMPLESERVICE< /app> < ipAddr> 172.21.40.134< /ipAddr> < status> UP< /status> < overriddenstatus> UNKNOWN< /overriddenstatus> < port enabled=" true" > 1935< /port> < securePort enabled=" false" > 443< /securePort> < countryId> 1< /countryId> < dataCenterInfo class=" com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo" > < name> MyOwn< /name> < /dataCenterInfo> < leaseInfo> < renewalIntervalInSecs> 30< /renewalIntervalInSecs> < durationInSecs> 90< /durationInSecs> < registrationTimestamp> 1404812488643< /registrationTimestamp> < lastRenewalTimestamp> 1404812609036< /lastRenewalTimestamp> < evictionTimestamp> 0< /evictionTimestamp> < serviceUpTimestamp> 1404812458545< /serviceUpTimestamp> < /leaseInfo> < metadata class=" java.util.Collections$EmptyMap" /> < appGroupName> UNKNOWN< /appGroupName> < homePageUrl> http://defonds-win7:1935/< /homePageUrl> < statusPageUrl> http://defonds-win7:1935/Status< /statusPageUrl> < healthCheckUrl> http://defonds-win7:1935/healthcheck< /healthCheckUrl> < vipAddress> sampleservice.mydomain.net< /vipAddress> < isCoordinatingDiscoveryServer> false< /isCoordinatingDiscoveryServer> < lastUpdatedTimestamp> 1404812488643< /lastUpdatedTimestamp> < lastDirtyTimestamp> 1404812513644< /lastDirtyTimestamp> < actionType> ADDED< /actionType> < /instance> < /application> < application> < name> EUREKA< /name> < instance> < hostName> localhost.localdomain< /hostName> < app> EUREKA< /app> < ipAddr> 127.0.0.1< /ipAddr> < status> UP< /status> < overriddenstatus> UNKNOWN< /overriddenstatus> < port enabled=" true" > 8080< /port> < securePort enabled=" false" > 443< /securePort> < countryId> 1< /countryId> < dataCenterInfo class=" com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo" > < name> MyOwn< /name> < /dataCenterInfo> < leaseInfo> < renewalIntervalInSecs> 30< /renewalIntervalInSecs> < durationInSecs> 90< /durationInSecs> < registrationTimestamp> 1404812408111< /registrationTimestamp> < lastRenewalTimestamp> 1404812618042< /lastRenewalTimestamp> < evictionTimestamp> 0< /evictionTimestamp> < serviceUpTimestamp> 1404812385938< /serviceUpTimestamp> < /leaseInfo> < metadata class=" java.util.Collections$EmptyMap" /> < appGroupName> UNKNOWN< /appGroupName> < homePageUrl> http://localhost.localdomain:8080/< /homePageUrl> < statusPageUrl> http://localhost.localdomain:8080/Status < /statusPageUrl> < healthCheckUrl> http://localhost.localdomain:8080/healthcheck < /healthCheckUrl> < vipAddress> eureka.mydomain.net< /vipAddress> < isCoordinatingDiscoveryServer> true< /isCoordinatingDiscoveryServer> < lastUpdatedTimestamp> 1404812408111< /lastUpdatedTimestamp> < lastDirtyTimestamp> 1404812385985< /lastDirtyTimestamp> < actionType> ADDED< /actionType> < /instance> < /application> < /applications>

apps__hashcode 变成 2 了。
能够看出多了一个 defonds-win7 名字的 instance，它的 IP 地址正是我执行 demo 的 PC 地址 172.21.40.134。訪问 http://serverIP:8080/eureka/ 也能够看到该 instance：

Eureka 的 Application Service client的注冊以及执行演示样例

文章图片

证明我们的 Application Service 已经成功注冊到该台 Eureka Server。
我们等待 Eureka Server 心跳訪问该 Application Service。或者自己手工訪问该 Application Service，以达成该服务器关闭条件，将其关闭。Application Service 成功取消注冊。
完整的 demo log 例如以下：
2014-07-08 10:06:54,124 INFO com.netflix.config.sources.URLConfigurationSource:125 [main] [< init> ] URLs to be used as dynamic configuration source: [file:/D:/javaprojects/test/bin/config.properties]
2014-07-08 10:06:54,259 INFO com.netflix.config.DynamicPropertyFactory:281 [main] [getInstance] DynamicPropertyFactory is initialized with configuration sources: [email protected]
2014-07-08 10:08:32,464 WARN com.netflix.appinfo.PropertiesInstanceConfig:349 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-08 10:08:35,592 WARN com.netflix.discovery.DefaultEurekaClientConfig:95 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-08 10:08:45,835 INFO com.netflix.appinfo.providers.EurekaConfigBasedInstanceInfoProvider:79 [main] [get] Setting initial instance status as: STARTING
2014-07-08 10:08:46,331 WARN com.netflix.discovery.DiscoveryClient:1339 [main] [getZoneOffset] DISCOVERY: Could not pick a zone based on preferred zone settings. My zone - defaultZone, preferSameZone- false. Defaulting to defaultZone
2014-07-08 10:08:49,276 INFO com.netflix.discovery.DiscoveryClient:646 [main] [fetchRegistry] Disable delta property : false
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:647 [main] [fetchRegistry] Single vip registry refresh property : null
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:648 [main] [fetchRegistry] Force full registry fetch : false
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:649 [main] [fetchRegistry] Application is null : false
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:650 [main] [fetchRegistry] Registered Applications size is zero : true
2014-07-08 10:08:49,278 INFO com.netflix.discovery.DiscoveryClient:652 [main] [fetchRegistry] Application version is -1: true
2014-07-08 10:08:49,705 INFO com.netflix.discovery.DiscoveryClient:992 [main] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/ with status code 200.
2014-07-08 10:08:49,706 INFO com.netflix.discovery.DiscoveryClient:758 [main] [getAndStoreFullRegistry] Getting all instance registry info from the eureka server
2014-07-08 10:08:50,501 INFO com.netflix.discovery.DiscoveryClient:765 [main] [getAndStoreFullRegistry] The response status is 200
2014-07-08 10:08:50,504 INFO com.netflix.discovery.DiscoveryClient:1056 [main] [initScheduledTasks] Starting heartbeat executor: renew interval is: 30
2014-07-08 10:09:20,508 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:09:20,535 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-2] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_1_, is fetching remote regions? false
2014-07-08 10:09:20,582 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-3] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 404.
2014-07-08 10:09:20,599 INFO com.netflix.discovery.DiscoveryClient$HeartbeatThread:1415 [DiscoveryClient-3] [run] DiscoveryClient_SAMPLESERVICE/defonds-win7 - Re-registering apps/SAMPLESERVICE
2014-07-08 10:09:20,600 INFO com.netflix.discovery.DiscoveryClient:509 [DiscoveryClient-3] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7: registering service...
2014-07-08 10:09:20,648 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-3] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE with status code 204.
2014-07-08 10:09:20,649 INFO com.netflix.discovery.DiscoveryClient:514 [DiscoveryClient-3] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7 - registration status: 204
Waiting for service to register with eureka..
2014-07-08 10:09:30,513 INFO com.netflix.discovery.DiscoveryClient$InstanceInfoReplicator:1476 [DiscoveryClient-2] [run] DiscoveryClient_SAMPLESERVICE/defonds-win7 - retransmit instance info with status UP
2014-07-08 10:09:30,514 INFO com.netflix.discovery.DiscoveryClient:509 [DiscoveryClient-2] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7: registering service...
2014-07-08 10:09:30,561 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE with status code 204.
2014-07-08 10:09:30,562 INFO com.netflix.discovery.DiscoveryClient:514 [DiscoveryClient-2] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7 - registration status: 204
2014-07-08 10:09:50,540 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:09:50,543 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-1] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:09:50,654 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 404.
2014-07-08 10:09:50,654 INFO com.netflix.discovery.DiscoveryClient$HeartbeatThread:1415 [DiscoveryClient-1] [run] DiscoveryClient_SAMPLESERVICE/defonds-win7 - Re-registering apps/SAMPLESERVICE
2014-07-08 10:09:50,654 INFO com.netflix.discovery.DiscoveryClient:509 [DiscoveryClient-1] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7: registering service...
2014-07-08 10:09:50,674 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE with status code 204.
2014-07-08 10:09:50,674 INFO com.netflix.discovery.DiscoveryClient:514 [DiscoveryClient-1] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7 - registration status: 204
Service started and ready to process requests..
2014-07-08 10:10:20,548 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:10:20,551 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-2] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions? false
2014-07-08 10:10:20,678 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:10:50,556 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:10:50,559 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-1] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:10:50,681 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-0] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:11:20,563 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:11:20,566 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-1] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:11:20,684 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:11:50,570 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:11:50,573 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-2] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions? false
2014-07-08 10:11:50,687 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:12:20,579 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-0] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:12:20,582 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-0] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:12:20,691 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-0] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
Client got connected..Processing request from the client
Received the request from the client.
Sending the response to the client...
2014-07-08 10:12:27,188 INFO com.netflix.discovery.DiscoveryClient:992 [main] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:12:27,189 INFO com.netflix.discovery.DiscoveryClient:603 [main] [unregister] DiscoveryClient_SAMPLESERVICE/defonds-win7 - deregister status: 200
Shutting down server.Demo over.
麻雀虽小五脏俱全，样例非常easy，但却完整地展现了一个 Application Service 客户端的 Eureka 生命周期。
參考资料