手工编写第一个Servlet

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 %> " >

< 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" >

<!--

-->

</ head >

< body >

< h1 > 第一个 Servlet 小例子 </ h1 >

< a href = "servlet/HelloServlet" > 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

手工编写第一个Servlet

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