一，应用场景：多个服务启动后可能会因为一些其他或者内在原因导致服务会挂掉，而我们维护人员不知情的情况下服务会一直挂到有人发现为止，
所以我们需要对Eureka的各个服务进行监听，当他们发生上线，下线，启动等，利用短信，邮箱等通知维护人员，维护人员会第一时间了解服务情况，进行处理。
二.Eureka服务状态分类
Eureka的server端会发出5个事件通知，分别是：
2.1 EurekaInstanceCanceledEvent 当有服务下线时会执行（掉线顾名思义，就是某个服务关闭时触发）
2.2 EurekaInstanceRegisteredEvent 当有服务注册时会执行（注册中心检测到有新的服务注册进来时触发）
2.3 EurekaInstanceRenewedEvent 当有服务续约时会执行（服务设置了心跳时间，如果下一次心跳还正常，就会把服务续约的信息更新到自身的Eureka Server中，然后再同步到其它Eureka Server中）
2.4 EurekaRegistryAvailableEvent Eureka 注册中心启动执行
2.5 EurekaServerStartedEvent Eureka Server 启动时执行
那接下来就好说了
第一步 : 引入maven依赖
略: 就是基本的依赖
第二步 : 监听服务
在网上查询了部分资料之后,发现部分的博客缺少一些东西,会对新手有很多的误导,在这里给出一个详细的步骤
Eureka服务端的配置
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | server: port: 9999spring: application: name: eureka01 security: user: name: root password: rooteureka: client: register-with-eureka: false #是否注册给服务中心，本身就是注册中心，所以不需要注册 service-url: defaultZone: http://root:root@localhost:9997/eureka/,http://root:root@localhost:9998/eureka/ #分别指向除自己外的注册中心地址，多个地址之间用“,”号隔开 server: enable-self-preservation: false # 测试时关闭自我保护机制，保证不可用服务及时踢出 eviction-interval-timer-in-ms: 5000 # 续期时间，即扫描失效服务的间隔时间（缺省为60*1000ms） |
服务配置这里的 关闭自我保护和清理间隔一定要打开 (虽然我也不知道为什么)
启动类
package com.web;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
/**
* Hello world!
*
*/
@SpringBootApplication
@EnableEurekaServer
public class EurekaServer extends WebSecurityConfigurerAdapter{
public static void main( String[] args ) {
SpringApplication.run(EurekaServer.class, args);
}
@Override
protected void configure(HttpSecurity http) throws Exception {
http.csrf().disable();//关闭csrf
super.configure(http);
}
}
服务监听类
package com.web.event;
import com.netflix.appinfo.InstanceInfo;
import lombok.extern.log4j.Log4j2;
import org.springframework.cloud.netflix.eureka.server.event.*;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;
@Log4j2
@Component
public class EurekaStateListener {
//private final static Logger logger = LoggerFactory.getLogger(EurekaStateListener.class);
@EventListener
public void listen(EurekaInstanceCanceledEvent event) {
log.info("服务{}已下线", event.getAppName());
log.info("server地址信息{}", event.getServerId());
}
@EventListener
public void listen(EurekaInstanceRegisteredEvent event) {
InstanceInfo instanceInfo = event.getInstanceInfo();
log.info("服务{}进行注册", instanceInfo.getAppName()+ instanceInfo.getHostName() +" "+ instanceInfo.getIPAddr() +" "+ instanceInfo.getPort());
}
@EventListener
public void listen(EurekaInstanceRenewedEvent event) {
log.info("服务{}进行续约", event.getServerId() +" "+ event.getAppName());
}
@EventListener
public void listen(EurekaRegistryAvailableEvent event) {
log.info("注册中心启动,{}", System.currentTimeMillis());
}
@EventListener
public void listen(EurekaServerStartedEvent event) {
log.info("注册中心服务端启动,{}", System.currentTimeMillis());
}
}
这里只是简单的记录,实际项目还是要做大量的通知，如果有注册中心是集群，挨个如上配置即可，我这就是集群的配置，以一个作文样列，就不每个都展示出来了。
第三步 : 客户端
客户端配置
server:
port: 8032
spring:
application:
name: productAclient
eureka:
instance:
lease-renewal-interval-in-seconds: 1 #每间隔10s，向服务端发送一次心跳
lease-expiration-duration-in-seconds: 2 #如果我2s之内没有给你发心跳，就代表我“死”了，将我踢出掉。
prefer-ip-address: true
hostname: 192.168.1.83
instance-id: ${eureka.instance.hostname}:${server.port}
client:
service-url:
defaultZone: http://root:root@localhost:9998/eureka/,http://root:root@localhost:9997/eureka/,http://root:root@localhost:9999/eureka/
这里的instance配置一定要写,很多新手忘记写这个导致服务下线无法被监听,因为服务下线后eureka没有将该服务踢出
启动类
package com.web;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
/**
* Hello world!
*
*/
@SpringBootApplication
@EnableEurekaClient
public class productA_Client {
public static void main( String[] args ) {
SpringApplication.run(productA_Client.class);
}
}
第四步 : 测试看效果
启动注册中心
2019-07-10 11:10:33.966 INFO 17696 --- [ Thread-30] c.n.e.r.PeerAwareInstanceRegistryImpl : Changing status to UP
2019-07-10 11:10:33.974 INFO 17696 --- [ Thread-30] e.s.EurekaServerInitializerConfiguration : Started Eureka Server
2019-07-10 11:10:33.977 INFO 17696 --- [ Thread-30] com.web.event.EurekaStateListener : 注册中心启动,1562728233974
2019-07-10 11:10:33.978 INFO 17696 --- [ Thread-30] com.web.event.EurekaStateListener : 注册中心服务端启动,1562728233978
2019-07-10 11:10:33.990 INFO 17696 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 9998 (http) with context path ''
2019-07-10 11:10:33.991 INFO 17696 --- [ main] .s.c.n.e.s.EurekaAutoServiceRegistration : Updating port to 9998
服务注册
2019-07-10 11:10:35.860 INFO 17696 --- [nio-9998-exec-3] com.web.event.EurekaStateListener : 服务PRODUCTACLIENT192.168.1.83 192.168.1.83 8031进行注册
2019-07-10 11:10:35.875 INFO 17696 --- [nio-9998-exec-3] c.n.e.registry.AbstractInstanceRegistry : Registered instance PRODUCTACLIENT/192.168.1.83:8031 with status UP (replication=true)
2019-07-10 11:10:35.876 INFO 17696 --- [nio-9998-exec-3] com.web.event.EurekaStateListener : 服务PRODUCTACLIENT192.168.1.83 192.168.1.83 8030进行注册
2019-07-10 11:10:35.876 INFO 17696 --- [nio-9998-exec-3] c.n.e.registry.AbstractInstanceRegistry : Registered instance PRODUCTACLIENT/192.168.1.83:8030 with status UP (replication=true)
2019-07-10 11:10:36.389 INFO 17696 --- [nio-9998-exec-4] com.web.event.EurekaStateListener : 服务PRODUCTACLIENT192.168.1.83 192.168.1.83 8031进行注册
2019-07-10 11:10:36.389 INFO 17696 --- [nio-9998-exec-4] c.n.e.registry.AbstractInstanceRegistry : Registered instance PRODUCTACLIENT/192.168.1.83:8031 with status UP (replication=true)
2019-07-10 11:10:36.390 INFO 17696 --- [nio-9998-exec-4] com.web.event.EurekaStateListener : 服务192.168.1.83:8030 PRODUCTACLIENT进行续约
2019-07-10 11:10:36.391 INFO 17696 --- [nio-9998-exec-4] com.web.event.EurekaStateListener : 服务192.168.1.83:8031 PRODUCTACLIENT进行续约
2019-07-10 11:10:37.407 INFO 17696 --- [nio-9998-exec-5] com.web.event.EurekaStateListener : 服务192.168.1.83:8030 PRODUCTACLIENT进行续约
2019-07-10 11:10:37.408 INFO 17696 --- [nio-9998-exec-5] com.web.event.EurekaStateListener : 服务192.168.1.83:8031 PRODUCTACLIENT进行续约
2019-07-10 11:10:38.415 INFO 17696 --- [nio-9998-exec-6] com.web.event.EurekaStateListener : 服务192.168.1.83:8030 PRODUCTACLIENT进行续约
2019-07-10 11:10:38.416 INFO 17696 --- [nio-9998-exec-6] com.web.event.EurekaStateListener : 服务192.168.1.83:8031 PRODUCTACLIENT进行续约
2019-07-10 11:10:38.967 INFO 17696 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry : Running the evict task with compensationTime 0ms
停止8082端口的服务
2018-07-24 09:41:59.599 INFO 16524 --- [a-EvictionTimer] com.lh.event.EurekaStateListener : 服务MEMBER已下线
2018-07-24 09:41:59.600 INFO 16524 --- [a-EvictionTimer] com.lh.event.EurekaStateListener : server地址信息DESKTOP-SHDQ5I0:member:8082
2018-07-24 09:41:59.601 INFO 16524 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry : Cancelled instance MEMBER/DESKTOP-SHDQ5I0:member:8082 (replication=false)
