JSP 中Servlet的自己实现-巨人网络通讯

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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

三实例

1、创建MyFirstServletDemo web project.

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HttpServlet
public 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/javaee
http://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