HttpServletDemo01.java
package com.fl.servlet; import java.io.IOException; import javax.servlet.Servlet; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class HttpServletDemo01 extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("get+++++++++++"); resp.getOutputStream().write("doGet+++被调用了".getBytes()); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("post+++++++++++++"); resp.getOutputStream().write("dopost+++被调用了".getBytes()); } }
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" 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_2_5.xsd"> <servlet> <!-- 类名 --> <servlet-name>httpGet</servlet-name><!-- 这里实现类名和实际运行的程序的连接 --> <!-- 所在的包 --> <servlet-class>com.fl.servlet.HttpServletDemo01</servlet-class> </servlet> <servlet-mapping> <servlet-name>httpGet</servlet-name><!-- 类名和浏览器输入的网址的连接 --> <!-- 访问的网址 --> <url-pattern>/httpGt</url-pattern> </servlet-mapping> </web-app>
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'index.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> This is my JSP page. <br> </body> <body> <form action="httpGt" method="post"> <input type="submit" value="submit"> </form> </body> </html>
也就是增加了这部分：
<body> <form action="httpGt" method="post"> -----------------这里的httpGt与xml中的类名一致，会请求post。 <input type="submit" value="submit"> </form> </body>
部署进tomcat后，
使用浏览器输入：http://localhost:8080/first_servlet/index.jsp
如何设置，使得在服务器启动时，就运行init：
只需要修改下该程序所对应的xml文件即可。
<servlet>
<!-- 类名 -->
<servlet-name>HelloWorld</servlet-name><!-- 这里实现类名和实际运行的程序的连接 -->
<!-- 所在的包 -->
<servlet-class>com.fl.servlet.ServletDemo01</servlet-class>
<load-on-startup>2</load-on-startup>
</servlet>
这个数字必须大于0。在大于0的基础上，各个服务之间，数字越小的越先初始化。