JSP 中Servlet的自己实现

2024-09-05 00:23:27

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JSP 中Servlet的自己实现

一步骤

1、继承HttpServlet
2、重写doGet()或者doPost()方法
3、在web.xml中注册Servlet

二 HttpServlet类继承图

JSP,Servlet

三实例

1、创建MyFirstServletDemo web project.

JSP,Servlet

2、编辑index.jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><%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%>" rel="external nofollow" >  <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" rel="external nofollow" >  --> </head>  <body> <h1>第一个Servlet小例子</h1> <a href="servlet/HelloServlet" rel="external nofollow" >Get方式请求HelloServlet</a> <form action="servlet/HelloServlet" method="post">    <input type="submit" value="Post方式请求HelloServlet"> </form> </body></html>

3、编写HelloServlet

package servlet; 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; //继承于HttpServletpublic class HelloServlet extends HttpServlet {   @Override  protected void doGet(HttpServletRequest request, HttpServletResponse response)      throws ServletException, IOException {    // TODO Auto-generated method stub    System.out.println("处理get（）请求...");    PrintWriter out = response.getWriter();    response.setContentType("text/html; charset=utf-8");    out.println("<strong>Hello Servlet!</strong><br>");  }   @Override  protected void doPost(HttpServletRequest request, HttpServletResponse response)      throws ServletException, IOException {    System.out.println("处理post（）请求...");    PrintWriter out = response.getWriter();    response.setContentType("text/html; charset=utf-8");    out.println("<strong>Hello Servlet!</strong><br>");  } }

4、编写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/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsd";> <display-name></display-name>  <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <servlet>  <servlet-name>HelloServlet</servlet-name>  <servlet-class>servlet.HelloServlet</servlet-class> </servlet> <servlet-mapping>   <servlet-name>HelloServlet</servlet-name>   <url-pattern>/servlet/HelloServlet</url-pattern> </servlet-mapping></web-app>

四运行结果

JSP,Servlet