servlet中启动后台线程

如果你希望在war包部署(启动)的时候,启动一个线程,有以下两种方法:

第一种方法:使用ServletContextListener,具体如下:

ServletContextListener使用方法,参考:

web.xml中添加以下行

com.mypackage.MyServletContextListener

下面是一个例子:

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) {
        }
    }
}

第二种方法:在Servlet的init()方法中创建线程,具体例子:

web.xml中添加以下行:特别需要注意的是设置load-on-startup为1,使得MyServlet可以在war部署时就加载

MyServlet
MyServlet
com.test.MyServlet
1

Servlet中init方法例子:

// This Happens Once and is Reused
public void init() throws ServletException {
super.init();
//start debugger in a  new thread
Thread thread = new Thread(new Runnable() {
public void run() {
try {
System.out.println("do anything you like...");
} catch (Exception e) {
e.printStackTrace();
}
System.out.print("debugger started.#");
}
});
thread.start();
}