正如它在 javadoc 中所说的那样
The threads in the pool will exist until it is explicitly shutdowned by
ExecutorService#shutdown()
如果我在 Tomcat 上有一个 Web 应用程序。在启动时它创建一个固定的线程池。我也调查过
public static void main(String ... strings) {
ExecutorService s = Executors.newFixedThreadPool(2);
s.submit(new Runnable() {
public void run() {
System.out.println("zzz");
}
});
}
在我将它们提交给 ExecutorService 之前,上面示例中的线程不存在。当 main
方法结束时,我在任务管理器(win 7 操作系统)的进程列表中看到一个 javaw.exe
。所以我假设运行该示例的 jvm 实例仍然存在。当我添加 s.shutdown()
- 进程列表中没有任何 java 进程。
问题一:当tomcat因为某些错误突然停止时,java进程会不会在内存中挂起(如果之前有任务提交到上述线程池);
问题 2:如果上一个问题的答案是肯定的,是否有一些方法可以使池中的线程成为守护进程,或者是否有一些方法可以处理此类 tomcat/myapp 停止调用 ExecutorService#shutdown()
最佳答案
Question 1: when the tomcat suddenly stops due to some errors, will the java process hang in the memory(if previously some tasks were submitted to thread pool mentioned above);
如果它没有关闭 ExecutorService
那么是的,它将挂起。
Question 2: if the answer to previouse question is yes, are there some ways to make threads in pool to be deamon...
是的。您可以提供一个线程工厂。
ExecutorService threadPool = newFixedThreadPool(numThreads,
new ThreadFactory() {
public Thread newThread(Runnable runnable) {
Thread thread = Executors.defaultThreadFactory().newThread(runnable);
thread.setDaemon(true);
return thread;
}
});
正如@matt b 提到的,另一种确保线程池关闭的机制是 define a shutdown hook/listener in Tomcat .
关于java - Executors.newFixedThreadPool 挂起的线程,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12425620/