看网上JqueryAjax三级联动的例子讲不是很全,代码也给的不是很全,给初学者带来一定的难度。小弟自己写了一个，可能有些地方不是很好，希望大家能够提出建议。
用的是Hibernate+struts2写的。
以代码来说话吧。
首先是index1.jsp页面
<%@ 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>Jquery-ajax三级联动</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"><script type="text/javascript" src="jquery-1.8.3.min.js"></script></head><script type="text/javascript"><!–页面加载时首先获得省–>$(function(){$.ajax({type:"post",url:"province",dataType:"json",async:false,success:function(data){var pro=eval("("+data+")");for(var i=0;i<pro.length;i++){$(".province").append("<option value="+pro[i].id+">"+pro[i].province+"</option>");}}});});</script><body>省：<select name="province" class="province"><option value="0">==请选择==</option></select>市：<select name="city" class="city"><option>==请选择==</option></select>区：<select name="town" class="town"><option>==请选择==</option></select> </body> <script type="text/javascript"> <!–省下拉列表框发生改变时候的事件–>$(".province").change(function(){var province_id=$(".province").val();//如果选择的是‘==请选择==’，不会执行去查找市，平且把已有的数据清空if($(".province").val()==0){$(".city option").remove();$(".city").append("<option value=0>==请选择==</option>");$(".town option").remove();$(".town").append("<option value=0>==请选择==</option>");return;}$.ajax({type:"post",//传一个省的id参数url:"city?province_id="+province_id,dataType:"json",async:false,success:function(city){var city=eval("("+city+")");for(var i=0;i<city.length;i++){$(".city").append("<option value="+city[i].id+">"+city[i].city+"</option>");}}});});//市下拉列表框发生改变时候的事件$(".city").change(function(){var city_id=$(".city").val();if($(".city").val()==0){$(".town option").remove();$(".town").append("<option value=0>==请选择==</option>");return;}$.ajax({type:"post",url:"town?city_id="+city_id,dataType:"json",async:false,success:function(town){var town=eval("("+town+")");for(var i=0;i<town.length;i++){$(".town").append("<option value="+town[i].id+">"+town[i].town+"</option>");}}});}); </script></html>
三个实体类：
1.Province实体类
package cn.yo.entity;import java.util.HashSet;import java.util.Set;public class Province implements java.io.Serializable {private Integer id;private String province;private Set cities = new HashSet(0);//省略了get,set方法2.City实体类
package cn.yo.entity;import java.util.HashSet;import java.util.Set;public class City implements java.io.Serializable {private Integer id;private Province province;private String city;private Set towns = new HashSet(0);//省略了get,set方法3.Town实体类
package cn.yo.entity;public class Town implements java.io.Serializable {private Integer id;private City city;private String town;//省略了get,set方法本人比较懒，用的是Hibernate框架，HibernateSessionFactory这个类大家会用Hibernate应该都会知道，我就不贴出了。
package cn.yo.dao;import java.util.List;import org.hibernate.Session;import cn.yo.entity.City;import cn.yo.entity.Province;import cn.yo.entity.Town;public class ProvinceDao {//查询全部省public List<Province> findProvince(){Session session=HibernateSessionFactory.getSession();String hql="from Province";List<Province> province=session.createQuery(hql).list();if(province.size()>0){return province;}else{return null;}}//根据省的Id查询该省下的全部市public List<City> findCityById(int id){Session session=HibernateSessionFactory.getSession();String hql="from City c where c.province.id=’"+id+"’";List<City> city=session.createQuery(hql).list();if(city.size()>0){return city;}else{return null;}}//根据市的Id查询该市下的全部镇public List<Town> findTownById(int id){Session session=HibernateSessionFactory.getSession();String hql="from Town t where t.city=’"+id+"’";List<Town> town=session.createQuery(hql).list();if(town.size()>0){return town;}else{return null;}}}接下来是action类
不要轻言放弃，否则对不起自己
