Question

发生异常时，我正在将对象发送到服务器（顺序约90个）。端点关闭，Logback会触发自定义STMP附加程序，该附加程序最多只能发送1封电子邮件。 10个日志，然后有一个延迟，其他日志被发送。 start()是否可能被频繁调用？

问题：
scheduler.scheduleAtFixedRate(this::sendEmail, 1, 1L, TimeUnit.HOURS);
在执行一次后不会延迟，而直接在另一时间执行，因此一小时之内可以收到很多电子邮件。

我必须更改延迟的工作原理？

洪水图片（如您所见，不到1小时就收到了两封电子邮件...）

附加代码：

public class ScheduledSMTPAppender extends SMTPAppender {

private final ThreadFactory tf = r -> {
    Thread t = new Thread(r, "ScheduledSMTPAppender Thread");
    t.setDaemon(true); //make daemon or it will prevent your program to exit
    return t;
};
private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1, tf);


private final List<ILoggingEvent> events = new ArrayList<>();

private int maxMessages = 10;

public ScheduledSMTPAppender() {
    super();
}

public ScheduledSMTPAppender(EventEvaluator<ILoggingEvent> eventEvaluator) {
    super(eventEvaluator);
}

@Override public void start() {
    super.start();
    scheduler.scheduleAtFixedRate(this::sendEmail, 1, 1L, TimeUnit.HOURS);
}

@Override protected void sendBuffer(CyclicBuffer<ILoggingEvent> cb, ILoggingEvent lastEventObject) {
    events.add(lastEventObject);

    if (events.size() > maxMessages)
    {
        sendEmail();
    }
}

//needs to be synchronized for thread safety
private synchronized void sendEmail() {
    try {
        if (events.isEmpty()){
            return;
        }
        ILoggingEvent lastEvent = events.get(events.size() - 1);
        events.remove(events.size() - 1);
        CyclicBuffer<ILoggingEvent> cb;

        if (events.isEmpty()) {
            cb = new CyclicBuffer<>(1);
        } else {
            cb = new CyclicBuffer<>(events.size());
            for (ILoggingEvent e : events){
                cb.add(e);
            }

        }
        super.sendBuffer(cb, lastEvent);
        events.clear();
    } catch (Exception e) {
        //Important to have a catch all here or the scheduled task will die
        addError("Error occurred while sending e-mail notification.", e);
    }
}

//this allows to make "maxMessages" a parameter of your appender
public int getMaxMessages() {
    return maxMessages;
}

public String getContentType() {
    return layout.getContentType();
}

public void setMaxMessages(int maxMessages) {
    this.maxMessages = maxMessages;

}

Answer 1

这似乎是问题所在

@Override 
public void start() {
    super.start();
    scheduler.scheduleAtFixedRate(this::sendEmail, 1, 1L, TimeUnit.HOURS);
}

此调度程序将为每个初始化的附加程序将sendEmail任务排队。您可以在每条日志行中记录对象的实例或一些ID，并在每次调用start时进行记录吗？那应该可以弄清楚情况。

请明确说明-我尝试了使用Sysout而不是记录器的相同代码（并在main方法中初始化了），并且按预期工作。这是代码

public class ScheduledSMTPAppender /*extends SMTPAppender*/ {

    private static final ThreadFactory tf = r -> {
        Thread t = new Thread(r, "ScheduledSMTPAppender Thread");
        t.setDaemon(true); //make daemon or it will prevent your program to exit
        return t;
    };
    private static final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1, tf);


    private final List<String> events = new ArrayList<>();

    private int maxMessages = 10;

    public static void main(String args[]) {
        ScheduledSMTPAppender app = new ScheduledSMTPAppender();
        System.out.println("started");
        Thread t = new Thread(() -> {
            try {
                scheduler.awaitTermination(1, TimeUnit.HOURS);
            } catch (Exception e) {
            }
        });
        System.out.println("awaiting termination");
        t.start();
        System.out.println("thread initiated");
        new Thread(() -> {
            // Thread to add events to check logs
            for (int i =0;i<10;i++)
            {app.addEvent("asd");
            try {Thread.sleep(1000);
            } catch(Exception e) {};}
        }).start();
    }


    public ScheduledSMTPAppender() {
        super();
        System.out.println("starting");
        scheduler.scheduleAtFixedRate(this::sendEmail, 1, 1L, TimeUnit.SECONDS);
    }

    /*
    public ScheduledSMTPAppender(EventEvaluator<String> eventEvaluator) {
        super(eventEvaluator);
    }

    @Override
    public void start() {
        super.start();
        scheduler.scheduleAtFixedRate(this::sendEmail, 1, 1L, TimeUnit.HOURS);
    }*/

    //@Override
    protected void sendBuffer(List<String> cb, String lastEventObject) {
        //System.out.println("sending email");
        events.add(lastEventObject);

        if (events.size() > maxMessages) {
            sendEmail();
        }
        System.out.println(new Date() + "sent email" + lastEventObject);
    }

    //needs to be synchronized for thread safety
    private synchronized void sendEmail() {
        try {
            if (events.isEmpty()) {
                return;
            }
            String lastEvent = events.get(events.size() - 1);
            events.remove(events.size() - 1);
            List<String> cb;

            if (events.isEmpty()) {
                cb = new ArrayList<>(1);
            } else {
                cb = new ArrayList<>(events.size());
                for (String e : events) {
                    cb.add(e);
                }

            }
            sendBuffer(cb, lastEvent);
            events.clear();
        } catch (Exception e) {
            //Important to have a catch all here or the scheduled task will die
            //addError("Error occurred while sending e-mail notification.", e);
        }
    }

    //this allows to make "maxMessages" a parameter of your appender
    public int getMaxMessages() {
        return maxMessages;
    }

//    public String getContentType() {
//        return layout.getContentType();
//    }

    public void setMaxMessages(int maxMessages) {
        this.maxMessages = maxMessages;

    }

    public void addEvent(String s) {
        events.add(s);
    }
}

自定义SMTPAppender中的scheduleAtFixedRate不会延迟

1 个答案: