由于实现了重新启动机制,我在使用ScheduledExecutorService
时遇到错误的行为。
问题-短
每次重新启动尝试都会创建一个新的计划任务,然后重新启动旧任务。
问题-长
该过程的目标是不时将消息发布到RabbitMQ中(它保持活动状态)。 RabbitMQ发生异常时,它将使用ExceptionObserver进行通知
发生异常。实现的ExceptionObserver停止服务,然后再次重新启动它。它尝试重新启动3次,如果成功重新启动,则计数为
重置为零。如果无法重新启动,则尝试计数将增加,并且如果达到尝试限制,它将关闭进程。
每次重新启动服务时,它都会创建一个新的“ KeepAliveService”并重新启动最后一个服务。因此,每次发生异常时,都会创建一个新服务,而旧的
服务重新启动。如果重启后发生1个异常,则有2个进程正在运行。如果发生2次异常,则有3个进程在运行,依此类推。
处理保持活动服务的服务类(启动/停止ScheduledExecutorService)
private KeepaliveExecutor keepaliveExecutor; // This is the runnable used inside the scheduledService
private ScheduledFuture futureTask; // The escheduled task
private ScheduledExecutorService scheduledService; // the scheduled service
private ExceptionObserver exceptionObserver; // The Exception Handler, which will handle the exceptions
public void startService( final int keepaliveTime ) throws IllegalArgumentException, FInfraException {
keepaliveExecutor = new KeepaliveExecutor( new RabbitMQService( settings ), settings );
keepaliveExecutor.setExceptionObserver( exceptionObserver );
scheduledService = Executors.newSingleThreadScheduledExecutor();
futureTask = scheduledService.scheduleAtFixedRate( keepaliveExecutor, 0, keepaliveTime, TimeUnit.MINUTES );
}
public void stopService() {
futureTask.cancel(true);
scheduledService.shutdown();
}
KeepaliveExecutor类
class KeepaliveExecutor implements Runnable {
private FInfraExceptionObserver exceptionObserver;
@Override
public void run() {
try {
final String keepAlive = JsonMapper.toJsonString( keepaliveMessage );
rabbitService.publishMessage( keepAlive );
keepaliveMessage.setFirtsPackage( false );
} catch( FInfraException ex ) {
if( exceptionObserver != null ) {
exceptionObserver.notifyExpcetion(ex);
}
}
}
ExceptionObserver实现类
public class FInfraExceptionHandler implements FInfraExceptionObserver {
private final FInfraServiceHandler finfraHandler;
public FInfraExceptionHandler(FInfraServiceHandler finfraHandler) {
this.finfraHandler = finfraHandler;
}
@Override
public void notifyExpcetion(Throwable ex) {
Util.logger.log( Level.INFO, "F-Infra Exception occurred", ex);
finfraHandler.stopService();
Util.logger.log( Level.INFO, "Waiting 30s for restarting..." );
Util.wait( 30, TimeUnit.SECONDS );
finfraHandler.startService();
}
FInfraServiceHandler类
public class FInfraServiceHandler {
private static final int ATTEMPT_LIMIT = 3;
private FInfraService finfraService;
private int keepaliveTime;
private int attempt;
public FInfraServiceHandler() {
this.finfraService = new FInfraService();
this.finfraService.setExceptionObserver(new FInfraExceptionHandler( this ));
this.attempt = 0;
}
void startService(){
if( attempt <= ATTEMPT_LIMIT ) {
try {
attempt++;
Util.logger.log(Level.INFO, "Starting F-Infra Service. Attemp[{0} of {1}]", new String[]{String.valueOf(attempt), String.valueOf(ATTEMPT_LIMIT)});
finfraService.startService( keepaliveTime );
} catch( FInfraException | RuntimeException ex ){
Util.logger.log(Level.INFO, "F-INFRA EXCEPTION", ex);
startService();
}
Util.logger.log( Level.INFO, "F-Infra started!");
attempt = 0;
return;
}
Util.logger.log( Level.INFO, "Restart attemp limit reached." );
Main.closeAll(new ShutdownException("It's not possible stablish a connection with F-Infra Service."));
}
public void stopService() {
if( attempt > 0 ){
Util.logger.log(Level.INFO, "Stpoping F-Infra...");
finfraService.stopService();
}
}
接下来是日志,告诉我有多个服务正在运行
jul 16, 2017 2:58:03 PM domain.FInfraServiceHandler startService
INFO: Starting F-Infra Service. Attemp[1 of 3]
jul 16, 2017 2:58:03 PM domain.FInfraServiceHandler startService
INFO: F-Infra started!
jul 16, 2017 5:01:15 PM domain.FInfraExceptionHandler notifyExpcetion
INFO: F-Infra Exception occurred
domain.FInfraException: java.net.UnknownHostException: rabbit.domain
at domain.RabbitMQService.openConnection(RabbitMQService.java:48)
at domain.RabbitMQService.publishMessage(RabbitMQService.java:66)
at domain.KeepaliveExecutor.run(KeepaliveExecutor.java:38)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.UnknownHostException: rabbit.domain
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.rabbitmq.client.impl.FrameHandlerFactory.create(FrameHandlerFactory.java:32)
at com.rabbitmq.client.impl.recovery.RecoveryAwareAMQConnectionFactory.newConnection(RecoveryAwareAMQConnectionFactory.java:34)
at com.rabbitmq.client.impl.recovery.AutorecoveringConnection.init(AutorecoveringConnection.java:91)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:670)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:722)
at domain.RabbitMQService.openConnection(RabbitMQService.java:45)
... 9 more
jul 16, 2017 5:01:15 PM domain.FInfraExceptionHandler notifyExpcetion
INFO: Waiting 30s for restarting...
jul 16, 2017 5:01:45 PM domain.FInfraServiceHandler startService
INFO: Starting F-Infra Service. Attemp[1 of 3]
jul 16, 2017 5:01:45 PM domain.FInfraServiceHandler startService
INFO: F-Infra started!
jul 16, 2017 6:01:58 PM domain.FInfraExceptionHandler notifyExpcetion
INFO: F-Infra Exception occurred
domain.FInfraException: java.net.UnknownHostException: rabbit.domain
at domain.RabbitMQService.openConnection(RabbitMQService.java:48)
at domain.RabbitMQService.publishMessage(RabbitMQService.java:66)
at domain.KeepaliveExecutor.run(KeepaliveExecutor.java:38)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.UnknownHostException: rabbit.domain
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.rabbitmq.client.impl.FrameHandlerFactory.create(FrameHandlerFactory.java:32)
at com.rabbitmq.client.impl.recovery.RecoveryAwareAMQConnectionFactory.newConnection(RecoveryAwareAMQConnectionFactory.java:34)
at com.rabbitmq.client.impl.recovery.AutorecoveringConnection.init(AutorecoveringConnection.java:91)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:670)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:722)
at domain.RabbitMQService.openConnection(RabbitMQService.java:45)
... 9 more
jul 16, 2017 6:01:58 PM domain.FInfraExceptionHandler notifyExpcetion
INFO: Waiting 30s for restarting...
jul 16, 2017 6:02:03 PM domain.FInfraExceptionHandler notifyExpcetion
INFO: F-Infra Exception occurred
domain.FInfraException: java.net.UnknownHostException: rabbit.domain
at domain.RabbitMQService.openConnection(RabbitMQService.java:48)
at domain.RabbitMQService.publishMessage(RabbitMQService.java:66)
at domain.KeepaliveExecutor.run(KeepaliveExecutor.java:38)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.UnknownHostException: rabbit.domain
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.rabbitmq.client.impl.FrameHandlerFactory.create(FrameHandlerFactory.java:32)
at com.rabbitmq.client.impl.recovery.RecoveryAwareAMQConnectionFactory.newConnection(RecoveryAwareAMQConnectionFactory.java:34)
at com.rabbitmq.client.impl.recovery.AutorecoveringConnection.init(AutorecoveringConnection.java:91)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:670)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:722)
at domain.RabbitMQService.openConnection(RabbitMQService.java:45)
... 9 more
jul 16, 2017 6:02:03 PM domain.FInfraExceptionHandler notifyExpcetion
INFO: Waiting 30s for restarting...
jul 16, 2017 6:02:28 PM domain.FInfraServiceHandler startService
INFO: Starting F-Infra Service. Attemp[1 of 3]
jul 16, 2017 6:02:28 PM domain.FInfraServiceHandler startService
INFO: F-Infra started!
jul 16, 2017 6:02:33 PM domain.FInfraServiceHandler startService
INFO: Starting F-Infra Service. Attemp[1 of 3]
jul 16, 2017 6:02:33 PM domain.FInfraServiceHandler startService
INFO: F-Infra started!
我不知道该怎么做才能关闭旧线程或使用当前线程重新启动。我试过的不是调用Thread.currentThread()。interrupt();在调用start方法之前,在ExceptionObserver类上进行操作。
但这是行不通的。
我不知道该怎么办。
最佳答案
在FInfraServiceHandler
类中,如果stopService
为零,则您的attempt
方法不执行任何操作。
public void stopService() {
if( attempt > 0 ){
Util.logger.log(Level.INFO, "Stpoping F-Infra...");
finfraService.stopService();
}
}
因此原始的
ScheduledExecutorService
继续前进。当我删除条件时,代码表现良好。请注意,顺便说一句,您在同一实例上从不同的线程调用
startService
和stopService
。我认为您需要在可变字段attempt
上进行某种同步。关于java - ScheduledExecutorService线程创建多个线程,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/45132856/