java - 事务中未到达finally{timer.cancel();}

Question

我们有以下事务，它在运行时发送心跳。然而，在某些情况下，心跳计时器永远不会停止，即使事务没有运行，系统也会不断发送心跳。我们在这里做错了什么吗？有没有更可靠的方法来停止心跳计时器(除了停止jboss)？

    @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
    @Asynchronous
    public void performUpdate(long requestSettingId) throws exception {
        try {
            // At this line a new Thread will be created
            final Timer timer = new Timer();
            // send the first heartbeat
            workerService.sendHeartBeat(requestSettingId);
            // At this line a new Thread will be created
            timer.schedule(new HeartbeatTask(setting.getId()), heartBeatInterval, heartBeatInterval);

            try {
                //Perform update
                //

            } finally {
                // terminate the HeartbeatTask
                timer.cancel();
            } catch (Exception e) {
            //Notify the task owner of the exception   
            }    
        }

    }

Answer 1

你的finally block 需要属于outer try，而不是inner try。如果timer.schedule失败，那么你的finally block 永远不会被执行。像这样的东西:

    public void performUpdate() throws exception {
    Timer timer = null;
    try {
        // At this line a new Thread will be created
        timer = new Timer();

        try {
            timer.cancel();
        } catch (Exception e) {
            //Notify the task owner of the exception
        }
    } finally {
        if ( timer != null ) timer.close();
    }
}