js城市省份二级联动 js使用xml数据载体实现城市省份二级联动效果

时间:2021-03-28 evan_qb 人气:0

想了解js使用xml数据载体实现城市省份二级联动效果的相关内容吗，evan_qb在本文为您仔细讲解js城市省份二级联动的相关知识和一些Code实例，欢迎阅读和指正，我们先划重点：js,xml,二级联动，下面大家一起来学习吧。

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:

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