servlet
1 //输出JSON格式的省份信息
2 @WebServlet("/ServletDemo1")
3 public class ServletDemo1 extends HttpServlet {
4 private static final long serialVersionUID = 1L;
5
6
7 public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
8 response.setContentType("text/html;charset=UTF-8");
9 PrintWriter out = response.getWriter();
10 String str = "{name:‘山东省‘}";
11 out.write(str);
12 }
json jsp中应用
eval函数用于转换成 json的文本 来让以后代码使用
1 <%@ page language="java" pageEncoding="utf-8"%>
2
3 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
4 <html>
5 <head>
6 <title>级联菜单</title>
7 <script type="text/javascript" src="./xmFile.js"> </script>
8 </head>
9 <body>
10 <select id="province" name="province">
11 <option value="">请选择....</option>
12 </select>
13 <select id="city" name="city">
14 <option value="">请选择.....</option>
15 </select>
16 <script type="text/javascript">
17 window.onload=function(){
18 var xhr = createXmlHttpRequest();
19 xhr.onreadystatechange=function(){
20 if(xhr.readyState==4){
21 if(xhr.status==200||xhr.status==304){
22 var data = xhr.responseText;//JSON数据，服务端是普通字符串返回的
23 var provinceJson = eval("("+data+")");//把普通的JSON字符串文本变成真正的JSON数据
24
25 var optionElement = document.createElement("option");
26 optionElement.setAttribute("value",provinceJson.name);
27 var textNode = document.createTextNode(provinceJson.name);
28 optionElement.appendChild(textNode);
29
30 document.getElementById("province").appendChild(optionElement);
31
32 }
33 }
34 }
35 xhr.open("GET","${pageContext.request.contextPath}/ServletDemo1?time="+new Date().getTime());
36 xhr.send(null);
37 }
38 function createXmlHttpRequest(){
39 var xmlHttp;
40 try{ //Firefox, Opera 8.0+, Safari
41 xmlHttp=new XMLHttpRequest();
42 }catch (e){
43 try{ //Internet Explorer
44 xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
45 }catch (e){
46 try{
47 xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
48 }catch (e){}
49 }
50 }
51 return xmlHttp;
52 }
53 </script>
54 </body>
55 </html>
json servlet通信 显示数据,布布扣,bubuko.com
时间： 2024-12-27 14:08:47