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
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<%@ 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:
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持移动技术网。
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