本文实例讲述了jQuery+jsp实现省市县三级联动效果的方法。分享给大家供大家参考，具体如下：
在这里，用MySQL数据库存储了全国所有的省市县地区信息(点击此处下载源代码)
使用过的jar包
google的Gson.jar
mysql-connector-java-5.1.13-bin.jar
将实验图贴出来：
显示页面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>省市区三级联动下拉菜单</title> <script type="text/javascript" src="/UploadFiles/2021-04-02/jquery-1.7.min.js">数据库交互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); } }希望本文所述对大家jQuery程序设计有所帮助。