在之前的几个代码示例中，都是利用@WebServlet注解类型给一个Servlet映射一条路径。使用web.xml(部署描述符总是命名为web.xml)是配置Servlet应用程序的另一种方法，该web.xml文件放在WEB-INF目录下。
使用@WebServlet注解的Servlet类：
package com.java.servlet.webxml; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet(name="SimpleServlet", urlPatterns= {"/simple"}) public class SimpleServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter writer = response.getWriter(); writer.print("<html><head></head><body>Simple Servlet</body></html>"); } }
可以不使用@WebServlet注解，而是在web.xml文件中进行配置
package com.java.servlet.webxml; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class SimpleServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter writer = response.getWriter(); writer.print("<html><head></head><body>Simple Servlet</body></html>"); } }
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <servlet> <servlet-name>SimpleServlet</servlet-name> <servlet-class>com.java.servlet.webxml.SimpleServlet</servlet-class> <load-on-startup>10</load-on-startup> </servlet> <servlet-mapping> <servlet-name>SimpleServlet</servlet-name> <url-pattern>/simple</url-pattern> </servlet-mapping> </web-app>