Ajax中利用jQuery简单实现异步交互 

 1 function verify(){
 2 //    alert("被点击了。。。。。。。");
 3     
 4     //得到id为loginName的标签对象
 5     var jqObject = $("#loginName");
 6     //得到文本框中的值
 7     var name = jqObject.val();
 8     //用JQ中的$.get()方法去访问服务器
 9     /*JQ中的get方法接受的参数
10      * get(url, [data], [callback], [type])
11      * url 待载入页面的URL地址
12      * data (可选) 待发送 Key/value 参数。
13      * callback (可选) 载入成功时回调函数。
14      * type (可选) 返回内容格式，xml, html, script, json, text, _default。
15 */
16     $.get("AjaxTestServlet?loginName=" + name,null,callback);
17 }
18 
19 //从服务器返回来的数据封装在callback函数的参数中
20 function callback(data){
21     alert(data);
22 }
 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 2 <html>
 3 <head>
 4 <meta http-equiv="Content-Type" content="text/html; charset=GBK">
 5 <title>Insert title here</title>
 6 <script type="text/javascript" src="jquery-1.7.1.js"></script>
 7 <script type="text/javascript" src="verify.js"></script>
 8 </head>
 9 <body>
10     <form name="form1" action="AjaxTestServlet" method="POST">
11         请输入注册用户名： <input name="loginName" type="text" id="loginName">
12         <input type="button" name="checkLoginName" value="有效性检查"
13             onclick="verify()"><br>
14     </form>
15 </body>
16 </html>
 1 import java.io.IOException;
 2 import java.io.PrintWriter;
 3 
 4 import javax.servlet.ServletException;
 5 import javax.servlet.annotation.WebServlet;
 6 import javax.servlet.http.HttpServlet;
 7 import javax.servlet.http.HttpServletRequest;
 8 import javax.servlet.http.HttpServletResponse;
 9 
10 /**
11  * Servlet implementation class AjaxTestServlet
12  */
13 @WebServlet("/AjaxTestServlet")
14 public class AjaxTestServlet extends HttpServlet {
15     private static final long serialVersionUID = 1L;
16        
17     /**
18      * @see HttpServlet#HttpServlet()
19 */
20     public AjaxTestServlet() {
21         super();
22         // TODO Auto-generated constructor stub
23     }
24 
25     /**
26      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
27 */
28     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
29         // TODO Auto-generated method stub
30         doPost(request,response);
31     }
32 
33     /**
34      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
35 */
36     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
37         // post按doGet()方法处理
38         response.setContentType("text/html");
39         PrintWriter out = response.getWriter();
40         //这里假设已经注册过了四位用户
41         String[] logined = {"admin","users","dywdyw","zhaom_916"};
42         //接收从客户端提交的loginName参数
43         String loginName = request.getParameter("loginName");
44         //创建一个存放响应内容的字符串
45         String responseContext = "true";
46         for (int i=0;i<logined.length;i++){
47             //遍历已注册用户列表，如果发现提交的注册名已存在，则修改响应内容
48             if (loginName.equals(logined[i]))responseContext = "false";
49         }
50         //将处理结果返回给客户端
51         out.println(responseContext);
52         out.flush();
53         out.close();
54     }
55 
56 }




posted @ 2012-03-18 15:47  半个灵魂  Views(337)  Comments(0)    收藏  举报