The Web.xml file is a deployment descriptor for a Java EE web application that defines the application's configuration information, including Servlet, Filter, Listener, and ServletContext initialization parameters. It is located in the WEB-INF directory and mainly uses the following elements when configuring: web-app: represents the entire web application. servlet: Defines servlets, including Servlet name, class name, and Servlet mapping. filter: Defines Filters, including Filter names, class names, and Filter mappings. listener: Determine

Web.xml configuration

What is a Web.xml file?

The Web.xml file is a deployment descriptor file for Java EE Web applications. It defines the configuration information of the application, such as Servlet, Filter, Listener, and ServletContext initialization parameters.

How to configure Web.xml?

The Web.xml file is located in the WEB-INF directory of the application. It follows an XML structure and contains the following main elements:

• web-app: represents the entire web application.
• servlet: Defines servlets, including Servlet name, class name, and Servlet mapping.
• filter: Defines Filters, including Filter names, class names, and Filter mappings.
• listener: defines the Listener, including the Listener name and class name.
• context-param: Defines the ServletContext initialization parameter, which can be used in Servlets.

Configuration example

Configure Servlet:

 <code class="xml"><servlet> <servlet-name>MyServlet</servlet-name> <servlet-class>com.example.MyServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>MyServlet</servlet-name> <url-pattern>/my-servlet</url-pattern> </servlet-mapping></code>

Configure Filter:

 <code class="xml"><filter> <filter-name>MyFilter</filter-name> <filter-class>com.example.MyFilter</filter-class> </filter> <filter-mapping> <filter-name>MyFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping></code>

Configure Listener:

 <code class="xml"><listener> <listener-class>com.example.MyListener</listener-class> </listener></code>

Configure ServletContext initialization parameters:

 <code class="xml"><context-param> <param-name>my-param</param-name> <param-value>my-value</param-value> </context-param></code>

The above is the detailed content of How to configure web.xml. For more information, please follow other related articles on the PHP Chinese website!