首先來看工程結構圖：
項目所需要的包，如下所示：
JSP代碼：
1 <%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
2 <%
3 String path = request.getContextPath();
4 String basePath = request.getScheme() + "://"
5 + request.getServerName() + ":" + request.getServerPort()
6 + path + "/";
7 System.out.println("basePath="+basePath);
8 %>
9 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
10 <html>
11 <head>
12 <title>JsonCase</title>
13 <script type="text/javascript" src="<%=basePath %>js/jquery-1.7.2.min.js"></script>
14 <script type="text/javascript">
15 $(function($) {
16 $("#record").append("當前測試頁面完成加載。<br/>");
17 });
18 function getFirstFloorValue(element) {
19 $("#record").append("<br/>獲取到信息：您將要取得第一級選項信息……");
20 $("#record").append("<br/>正在使用ajax為您獲取數據，您可以繼續停留在頁面並進行其他操作。");
21 $.ajax({
22 url : 'ValueGetController',
23 type : 'post',
24 data : 'action=GetFirstFloorValue',
25 datatype : 'json',
26 success : function(data) {
27 $("#record").append("<br/>操作成功，正在為您准備數據……");
28 $(element).empty();
29 $("#record").append("<br/>清除原始數據成功！");
30 var ops = $.parseJSON(data);
31 $("#record").append("<br/>即時數據准備成功！");
32 for ( var i = 0; i < ops.length; i++)
33 $(element).append(
34 "<option value=\"" + ops[i] + "\">" + ops[i]
35 + "</option>");
36 $("#record").append("<br/>更新列表成功！<br/>");
37 }
38 });
39
40
41 }
42 </script>
43 </head>
44
45 <body>
46 <div>
47
48 <select id="select1" onfocus=getFirstFloorValue(this)>
49 <option value="1">點擊取值</option>
50 </select>
51 </div>
52 <dir>
53 <h3>記錄信息：</h3>
54 <span id="record"></span>
55 </dir>
56 </body>
57 </html>
JAVA servlet代碼：
1 package servlet;
2
3 import java.io.IOException;
4 import java.io.PrintWriter;
5
6 import javax.servlet.ServletException;
7 import javax.servlet.http.HttpServlet;
8 import javax.servlet.http.HttpServletRequest;
9 import javax.servlet.http.HttpServletResponse;
10 import net.sf.json.JSONArray;
11
12 public class ValueGetController extends HttpServlet {
13
14 private static final long serialVersionUID = -1293610555518403602L;
15
16
17 /**
18 * Constructor of the object.
19 */
20 public ValueGetController() {
21 super();
22 }
23
24 /**
25 * Destruction of the servlet. <br>
26 */
27 public void destroy() {
28 super.destroy(); // Just puts "destroy" string in log
29 // Put your code here
30 }
31
32 /**
33 * The doGet method of the servlet. <br>
34 *
35 * This method is called when a form has its tag value method equals to get.
36 *
37 * @param request the request send by the client to the server
38 * @param response the response send by the server to the client
39 * @throws ServletException if an error occurred
40 * @throws IOException if an error occurred
41 */
42 public void doGet(HttpServletRequest request, HttpServletResponse response)
43 throws ServletException, IOException {
44
45 doPost(request, response);
46
47
48 }
49
50 /**
51 * The doPost method of the servlet. <br>
52 *
53 * This method is called when a form has its tag value method equals to post.
54 *
55 * @param request the request send by the client to the server
56 * @param response the response send by the server to the client
57 * @throws ServletException if an error occurred
58 * @throws IOException if an error occurred
59 */
60 public void doPost(HttpServletRequest request, HttpServletResponse response)
61 throws ServletException, IOException {
62
63 request.setCharacterEncoding("GBK");
64 response.setContentType("text/html;charset=gbk");
65 PrintWriter out = response.getWriter();
66 String action = request.getParameter("action");
67 System.out.println("action"+action);
68 if (action.equals("GetFirstFloorValue")) {
69 String[] str = GetFirstFloorValue();
70 JSONArray ja = JSONArray.fromObject(str);
71 String json = ja.toString();
72 out.print(json);
73 System.out.println(json);
74 out.flush();
75 out.close();
76 return;
77 }
78 out.flush();
79 out.close();
80 }
81
82 private String[] GetFirstFloorValue() {
83 String[] str = new String[4];
84 str[0] = "test1";
85 str[1] = "test2";
86 str[2] = "test3";
87 str[3] = "test4";
88 return str;
89
90 }
91
92
93
94 }
關於servlet的web.xml配置：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <web-app version="2.5" 3 xmlns="http://java.sun.com/xml/ns/javaee" 4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 5 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 6 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 7 <servlet> 8 <description>This is the description of my J2EE component</description> 9 <display-name>This is the display name of my J2EE component</display-name> 10 <servlet-name>ValueGetController</servlet-name> 11 <servlet-class>servlet.ValueGetController</servlet-class> 12 </servlet> 13 14 <servlet-mapping> 15 <servlet-name>ValueGetController</servlet-name> 16 <url-pattern>/ValueGetController</url-pattern> 17 </servlet-mapping> 18 19 20 21 <welcome-file-list> 22 <welcome-file>index.jsp</welcome-file> 23 </welcome-file-list> 24 </web-app>
