Ajax随笔 

<%@ page language="java" import="java.util.*" pageEncoding="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 'ajax.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">
    -->
    <script type="text/javascript">
    var xmlHttpRequest = null; //声明一个空对象以接收XMLHttpRequest对象
    function ajaxSubmit()
    {
        if(window.ActiveXObject) // IE浏览器
        {
            xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP");
        }
        else if(window.XMLHttpRequest) //除IE外的其他浏览器实现
        {
            xmlHttpRequest = new XMLHttpRequest();
        }
        
        if(null != xmlHttpRequest)
        {
            var v1 = document.getElementById("value1ID").value;
            var v2 = document.getElementById("value2ID").value;
            xmlHttpRequest.open("POST", "AjaxServlet", true);        //xmlHttpRequest.open("GET", "AjaxServlet?v1="+v1+"&v2="+v2, true);
            //关联好ajax的回调函数
            xmlHttpRequest.onreadystatechange = ajaxCallback;
            //真正向服务器端发送数据
            // 使用post方式提交，必须要加上如下一行,表单默认编码方式
            xmlHttpRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
            xmlHttpRequest.send("v1=" + v1 + "&v2=" + v2);            //xmlHttpRequest.send(null);
        }
    }
    function ajaxCallback()
    {
        //1.构造对象,2.发送请求,3.收到响应,4.处理响应
        if(xmlHttpRequest.readyState == 4)
        {
            if(xmlHttpRequest.status == 200)
            {
                var responseText = xmlHttpRequest.responseText;
                
                document.getElementById("div1").innerHTML = responseText;
            }
        }
    }
    </script>
  </head>
  <body>
    <input type="button" value="get content from server" onclick="ajaxSubmit();"><br>
    <input type="text" name="value1" id="value1ID"><br>
    <input type="text" name="value2" id="value2ID"><br>
    <div id="div1"></div>
  </body>
</html>
package com.shengsiyuan.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;

public class AjaxServlet extends HttpServlet
{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException
    {
        System.out.println("doGet invoked");

        process(req, resp);
    }

    private void process(HttpServletRequest req, HttpServletResponse resp)
            throws IOException
    {
        String v1 = req.getParameter("v1");
        String v2 = req.getParameter("v2");

        System.out.println("v1=" + v1 + ", v2=" + v2);
        
        String v3 = String.valueOf(Integer.valueOf(v1) + Integer.valueOf(v2));

        PrintWriter out = resp.getWriter();

        // try
        // {
        // Thread.sleep(5000);
        // }
        // catch (InterruptedException e)
        // {
        // e.printStackTrace();
        // }

        resp.setHeader("pragma", "no-cache");
        resp.setHeader("cache-control", "no-cache");

        out.println(v3);

        out.flush();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException
    {
        System.out.println("doPost invoked");

        this.process(req, resp);
    }
}

 

posted @ 2013-08-03 16:29  牧之丨  阅读(237)  评论(0)  编辑  收藏  举报