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Ajax局部刷新應用案例

 Ajax局部刷新在之前的文章中也有介紹過,下面以一個登錄的例子為大家介紹下其具體的使用

二話不說了,直接給代碼,相信需要的都是代碼而不是廢話一堆……  1.java代碼:   代碼如下: package tt;    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 TestA extends HttpServlet {    private static final long serialVersionUID = -7999241892841130740L;    protected void doGet(HttpServletRequest request,  HttpServletResponse response) throws ServletException, IOException {  request.setCharacterEncoding("utf-8");  String name = request.getParameter("name");    response.setContentType("text/xml; charset=utf-8");  response.setHeader("Cache-Control", "no-cache");  PrintWriter out = response.getWriter();  out.println("<pront>");  if (name.equals("yangjinde")) {  out.println("<content>" + "對不起,'yangjinde'此名已經注冊" + "</content>");  } else {  out.println("<content>" + "可以注冊哦" + "</content>");  }  out.println("</pront>");  out.close();  }  }    2.jsp代碼:  代碼如下: <%@ 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 '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">  <script>  //設一個變量  var XMLHttpReq=false;  //創建一個XMLHttpRequest對象  function createXMLHttpRequest(){  if(window.XMLHttpRequest){ //Mozilla  XMLHttpReq=new XMLHttpRequest();  }  else if(window.ActiveXObject){  try{  XMLHttpReq=new ActiveXObject("Msxml2.XMLHTTP");  }catch(e){  try{  XMLHttpReq=new ActiveXObject("Microsoft.XMLHTTP");  }catch(e){}  }  }  }  //發送請求函數  function send(url){  createXMLHttpRequest();  XMLHttpReq.open("GET",url,true);  XMLHttpReq.onreadystatechange=proce; //指定響應的函數  XMLHttpReq.send(null); //發送請求  }  function proce(){  if(XMLHttpReq.readyState==4){ //對象狀態  if(XMLHttpReq.status==200){//信息已成功返回,開始處理信息  var res=XMLHttpReq.responseXML.getElementsByTagName("content")[0].firstChild.data;  window.alert(res);  document.getElementById("data").innerHTML = res;  document.getElementById("name").value = res;  }else{  window.alert("不好意思,所請求的頁面有異常");  }  }  }  //身份驗證  function check(){  var name=document.getElementById("name").value;  if(name==""){  alert("請輸入內容哦");  return false;  }  else{  send('login?name='+name);  }  }    </script>  </head>    <body>  <form action="login" method="post">  <tr><td>姓名: <input id="name" type="text" name="name"/>  <input type="button" value="點我試試看" onClick="check()"/>  </td>  </tr>  <tr><td><div id="data">等下我會變哦!!</div></td></tr>  </form>  </body>  </html>    3.xml配置文件代碼:  復制代碼 代碼如下: <?xml version="1.0" encoding="UTF-8"?>  <web-app version="2.4"  xmlns="http://java.sun.com/xml/ns/j2ee"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">  <servlet>  <servlet-name>login</servlet-name>  <servlet-class>tt.TestA</servlet-class>  </servlet>    <servlet-mapping>  <servlet-name>login</servlet-name>  <url-pattern>/login</url-pattern>  </servlet-mapping>  <welcome-file-list>  <welcome-file>index.jsp</welcome-file>  </welcome-file-list>  </web-app>     
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