本文實例講述了jQuery+jsp實現省市縣三級聯動效果的方法。分享給大家供大家參考，具體如下：
在這里，用MySQL數據庫存儲了全國所有的省市縣地區信息(點擊此處下載源代碼)
使用過的jar包
google的Gson.jar
mysql-connector-java-5.1.13-bin.jar
將實驗圖貼出來：
顯示頁面index.jsp
<%@ 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%>"> <title>省市區三級聯動下拉菜單</title> <script type="text/javascript" src="<%=path %>/js/jquery/jquery-1.7.min.js"></script> <script type="text/javascript" src="<%=path %>/js/json/json-minified.js"></script> </head> <body> <table> <tr> <td> 省份： <select name="province" id="province" onchange="onSelectChange(this,'city');"></select> 城市： <select name="city" id="city" onchange="onSelectChange(this,'district');"> <option value="">請選擇</option> </select> 區(縣)： <select name="district" id="district"> <option value="">請選擇</option> </select> </td> </tr> </table> </body></html><script type="text/javascript">function onSelectChange(obj,toSelId){ setSelect(obj.value,toSelId);}function setSelect(fromSelVal,toSelId){ //alert(document.getElementById("province").selectedIndex); document.getElementById(toSelId).innerHTML=""; jQuery.ajax({ url: "<%=path%>/getDropdownDataServlet", cache: false, data:"parentId="+fromSelVal, success: function(data){ createSelectObj(data,toSelId); } });}function createSelectObj(data,toSelId){ var arr = jsonParse(data); if(arr != null && arr.length>0){ var obj = document.getElementById(toSelId); obj.innerHTML=""; var nullOp = document.createElement("option"); nullOp.setAttribute("value",""); nullOp.appendChild(document.createTextNode("請選擇")); obj.appendChild(nullOp); for(var o in arr){ var op = document.createElement("option"); op.setAttribute("value",arr[o].id); //op.text=arr[o].name;//這一句在ie下不起作用，用下面這一句或者innerHTML op.appendChild(document.createTextNode(arr[o].name)); obj.appendChild(op); } }}setSelect('1','province');</script>數據庫交互GetDropdownDataServlet
public class GetDropdownDataServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String parentId = request.getParameter("parentId"); if (parentId == null || parentId == "") { parentId = "0"; } Connection conn = null; String json = ""; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection("jdbc:mysql://localhost/dropdown", "root", "root"); Statement stat = conn.createStatement(); ResultSet rs = stat .executeQuery("select region_id,region_name from region where parent_id = " + parentId); ArrayList rsList = new ArrayList(); Map map = null; while (rs.next()) { map = new HashMap(); map.put("id", rs.getInt(1)); map.put("name", rs.getString(2)); rsList.add(map); } rs = null; Gson gson = new Gson(); json = gson.toJson(rsList); System.out.println("json=" + json); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } response.setCharacterEncoding("UTF-8"); response.getWriter().print(json); }}希望本文所述對大家jQuery程序設計有所幫助。
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