js使用xml数据载体实现城市省份二级联动效果
本文实例为大家分享了使用xml数据载体实现城市省份二级联动的具体代码，供大家参考，具体内容如下
首先写好前台页面testProvince.jsp，将请求通过open、send发送到服务器
<%@ 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%>" rel="external nofollow" >
<title>二级联动</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">
<style type="text/css">
select{
width:111px;
}
</style>
</head>
<body>
<select id="provinceID">
<option>选择省份</option>
<option>湖南</option>
<option>广东</option>
</select>
<select id="cityID">
<option>选择城市</option>
</select>
</body>
<script type="text/javascript">
//创建ajax对象
function createAjax(){
var ajax = null;
try{
ajax = new ActiveXObject("microsoft.xmlhttp");
}catch(e){
try{
ajax = new XMLHttpRequest();
}catch(e1){
alert("请更换浏览器");
}
}
return ajax;
}
</script>
<script type="text/javascript">
document.getElementById("provinceID").onchange = function(){
//清空城市除了第一项
var cityElem = document.getElementById("cityID");
cityElem.options.length = 1;
//获取选中的省份
var province = this.value;
//进行编码处理
province = encodeURI(province);
if("选择省份" != province){
var ajax = createAjax();
//提交方式为GET
var method = "GET";
//提交路径为servlet路径
var url = "${pageContext.request.contextPath}/ProvinceServlet?time=" + new Date().getTime()+
"&province=" +province;
//准备发送异步请求
ajax.open(method, url);
//由于是get请求，所以不需要设置请求头
//发送请求
ajax.send(null);
//监听服务器响应状态的变化
ajax.onreadystatechange = function(){
//响应状态为4 表示ajax已经完全接受到服务器的数据了
if(ajax.readyState == 4){
//接收到的数据正常
if(ajax.status == 200){
//获取服务器传来的html数据
var xmlDocument = ajax.responseXML;
//进行dom操作解析xml
//解析xml数据
var citys = xmlDocument.getElementsByTagName("city");
for(var i = 0; i< citys.length;i++){
//获取xml中的值 :不能用innerHTML,要用nodeValue
var city = citys[i].firstChild.nodeValue;
//创建option
var optElement = document.createElement("option");
optElement.innerHTML = city;
//获取city
var cityElems = document.getElementById("cityID");
cityElems.appendChild(optElement);
}
}
}
}
}
}
</script>
</html>
然后在后台ProvinceServlet中通过GET方式获取请求，将返回的数据以O（输出）流的方式发送出去,上面代码的ajax.responseXML获取输出的数据，并进行dom操作
public class ProvinceServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
resp.setCharacterEncoding("utf-8");
String province = req.getParameter("province");
//重新编码
province = new String(province.getBytes("ISO-8859-1"),"utf-8");
//设置格式为xml
resp.setContentType("text/xml;charset=utf-8");
//获取字符输出流
PrintWriter pw = resp.getWriter();
//拼接xml头
pw.write("<?xml version='1.0' encoding='UTF-8'?>");
pw.write("<citys>");
if ("湖南".equals(province)) {
pw.write("<city>长沙</city>");
pw.write("<city>株洲</city>");
pw.write("<city>湘潭</city>");
pw.write("<city>岳阳</city>");
}else if("广东".equals(province)){
pw.write("<city>广州</city>");
pw.write("<city>深圳</city>");
pw.write("<city>中山</city>");
}
pw.write("</citys>");
pw.flush();
pw.close();
}
}
运行结果如下:
