记一次定时任务的时间表达式的错

一 错误地方

2018-09-17 14:34:30,474 [localhost-startStop-1] WARN  org.apache.catalina.loader.WebappClassLoaderBase - The web application [ROOT] appears to have started a thread named [RxIoScheduler-1 (Evictor)] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
 java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
 java.lang.Thread.run(Thread.java:745)
2018-09-17 14:34:30,475 [localhost-startStop-1] WARN  org.apache.catalina.loader.WebappClassLoaderBase - The web application [ROOT] appears to have started a thread named [globalEventExecutor-2-2] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
 java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
 io.netty.util.concurrent.GlobalEventExecutor.takeTask(GlobalEventExecutor.java:90)
 io.netty.util.concurrent.GlobalEventExecutor$TaskRunner.run(GlobalEventExecutor.java:230)
 io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
 java.lang.Thread.run(Thread.java:745)
Disconnected from the target VM, address: '127.0.0.1:55751', transport: 'socket'

Process finished with exit code 1

遇见这种错误，我的心就拔凉拔凉的，以前遇到这种不报具体错误的，只得用排除法一步一步的排查！

1.出现这种错误的可能原因： 循环调用，导致堆栈溢出；

　　解决办法：把自己刚写的代码利用排除法，一步一步的排除；

2.出现这种错误的可能原因： 配置文件获取不到；

　　有的是用SpringCloud搭建的框架，有个config-server 来获取配置文件，这种有个坑 不同的局域网内，是获取不到配置文件的，比如你把config-server部署到阿里云上，你在你本地是获取不到配置文件的，再比如，你把配置中心部署到华南地区，那么阿里云在华北地区的是获取不到配置文件的   坑。。。。。。。。。。。。。。

3.经过排除法才找到这样的一个错：

    /**
     * 每天凌晨3点执行
     */
    @Scheduled(cron = "0 0 3 * * * ?")
    public void deleteOverdueFile(){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(new Date());
        calendar.add(Calendar.DATE,-30);
        log.debug("过期时间："+sdf.format(calendar.getTime()));
        weixinChatUploadLogService.deleteOverdueFile(calendar.getTime());
    }

   咋眼一看没啥问题，可是你万万想不到 定时任务的时间表达式写错了  此处应该有个捂脸的表情！

    /**
     * 每天凌晨3点执行
     */
    @Scheduled(cron = "0 0 3 * * ?") //这样才是对的
    public void deleteOverdueFile(){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(new Date());
        calendar.add(Calendar.DATE,-30);
        log.debug("过期时间："+sdf.format(calendar.getTime()));
        weixinChatUploadLogService.deleteOverdueFile(calendar.getTime());
    }

  在此给大家教一种排除错误的办法  那就是  最常用的   排除法！ 

　　当你不知道问题出在哪里时。你把你最近写的代码，有可能出错的地方注释掉，然后慢慢的缩小错误范围 ！

　　　　哈哈 这样慢慢的你就是排雷小能手!

　　　　此处应该有掌声！