Tomcat servlet应用程序的后台线程 [英] Background Thread for a Tomcat servlet app

问题描述

我对Tomcat不太熟悉，在我看来它基本上被抽象为cgi服务器，可以在调用之间保存JVM - 我知道它可以做更多的事情。

I am not very familiar with Tomcat, in my head it is basically abstracted as a cgi server that saves the JVM between calls -- I know it can do a lot more than that, though.

我正在寻找一种在Tomcat服务器启动时启动后台线程的方法，它会定期更新服务器上下文（在我的特定情况下）这是一个线程，它从一些其他服务中侦听心跳并更新可用性信息，但可以想象这有多种用途）。

I am looking for a way to launch a background thread when a Tomcat server starts, which would periodically update the Server Context (in my particular case this is a thread that listens to heartbeats from some other services and updates availability information, but one can imagine a variety of uses for this).

有没有一种标准方法可以做到这一点？启动和更新/查询Context？

Is there a standard way to do this? Both the launching, and the updating/querying of the Context?

任何指向相关文档和/或代码示例的指针都将非常感激。

Any pointers to the relevant documentation and/or code samples would be much appreciated.

推荐答案

如果要在部署WAR时启动线程，可以在web.xml中定义上下文侦听器：

If you want to start a thread when your WAR is deployed, you can define a context listener within the web.xml:

<web-app>
    <listener>
       <listener-class>com.mypackage.MyServletContextListener</listener-class>
    </listener>
</web-app>

然后实现这样的类：

public class MyServletContextListener implements ServletContextListener {

    private MyThreadClass myThread = null;

    public void contextInitialized(ServletContextEvent sce) {
        if ((myThread == null) || (!myThread.isAlive())) {
            myThread = new MyThreadClass();
            myThread.start();
        }
    }

    public void contextDestroyed(ServletContextEvent sce){
        try {
            myThread.doShutdown();
            myThread.interrupt();
        } catch (Exception ex) {
        }
    }
}

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