问题 - 简短

Question

由于实施了重启机制，我使用ScheduledExecutorService面临错误行为。

问题 - 简短

每次重启尝试都会创建一个新的计划任务并重新启动旧任务。

问题 - 长

流程目标是不时向RabbitMQ发布消息（它是keep-alive）。当RabbitMQ发生异常时，它使用ExceptionObserver进行通知发生了异常。实现的ExceptionObserver停止服务并再次重新启动它。尝试重启3次，如果重启成功，则计数为重置为零。如果无法重新启动，则尝试计数会增加，如果达到尝试限制，则会关闭该过程。

每次重新启动服务时，它都会创建一个新的“KeepAliveService”并重新启动上一个服务。因此，每次发生异常时，都会创建一个新服务并创建旧服务服务重新启动。如果重启后出现1个异常，则有2个进程在运行。如果发生2个异常，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();
    }
}

以下是日志，它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!

我不知道如何关闭旧线程或使用当前的线程重新启动。我尝试过什么来调用Thread.currentThread（）。interrupt（）;在调用start方法之前在ExceptionObserver类上。但这不起作用。

我不知道该怎么做。

Answer 1

在FInfraServiceHandler课程中，如果stopService为零，则您的attempt方法不会执行任何操作。

public void stopService() {
    if( attempt > 0 ){
        Util.logger.log(Level.INFO, "Stpoping F-Infra...");
        finfraService.stopService();
    }
}

原来ScheduledExecutorService继续前进。当我删除条件时，代码表现良好。

顺便说一句，请注意，您在同一个实例上从不同的线程调用startService和stopService。我认为你需要在可变字段attempt上进行某种同步。

ScheduledExecutorService线程创建多个线程

问题 - 简短

问题 - 长

1 个答案: