java - 如何在Servlet中找到监听器？

Question

这个问题已经有答案了:

How do servlets work? Instantiation, sessions, shared variables and multithreading (8 个回答)

已关闭 7 年前。

现在我正在阅读 servlet 操作监听器。我的问题是容器如何知道哪个类是监听器？

Answer 1

监听器在 web.xml 文件描述符中定义。请参阅docs了解更多信息。值得注意的是:

Create an event listener class by implementing the appropriate interface or interfaces of the javax.servlet package or javax.servlet.http package.

Event listeners are declared in the application web.xml deployment descriptor through elements under the top-level element. Each listener has its own element, with a subelement specifying the class name. Within each event category, event listeners should be specified in the order in which you would like them to be invoked when the application runs.