在 Google App Engine 上启动服务器上的运行脚本，在 Java

Question

My question is similar to this one , but with regard to Java instead of Python.

How can I force some Java code to run whenever a new instance of a Google App Engine server starts?

Thanks!

Answer 1

in google app engine, your java code is executed within the servlet environment. thus, you could define listeners to boostrap your startup code. to do this, you need to implement your startup code in the listener and define the listener in your web.xml:

listner class:

package test;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class MyContextListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        // startup code here
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        // shutdown code here
    }

}

web.xml:

<web-app>
    <listener>
        <listener-class>test.MyContextListener</listener-class>
    </listener>

<!-- your other web configuration -->

</web-app>

Answer 2

Same answer, put a call in your main function to whatever setup you need to run, but make sure you allow checks where you won't run that setup if you already have a server instance running.