Hibernate+DWR无刷新三级联动

来源：互联网发布：苹果测评电池软件编辑：程序博客网时间：2024/06/05 18:54

看网上DWR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。

DWR是一个用于改善web页面与Java类交互的远程服务器端Ajax开源框架，可以帮助开发人员开发包含AJAX技术的网站。它可以允许在浏览器里的代码使用运行在WEB服务器上的JAVA函数，就像它就在浏览器里一样。看代码吧.

使用DWR必须先加DWR的jar包.我这使用的是2.0.5

index.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>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="dwr/engine.js"></script><script type="text/javascript" src="dwr/util.js"></script><!-- 导入DWR 为Java 对象动态生成的JavaScript 文件--><script type="text/javascript" src="dwr/interface/mydwr.js"></script><script type="text/javascript" src="jquery-1.8.3.min.js"></script></head><script type="text/javascript">$(function(){mydwr.findProvince(function(pro){for(var i=0;i<pro.length;i++){$(".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">  $(".province").change(function(){  if($(".province").val()==0){  $(".city option").remove();  $(".city").append("<option value=0>==请选择==</option>");$(".town option").remove();  $(".town").append("<option value=0>==请选择==</option>");  return;  }mydwr.findCityById($(this).val(),function(city){$(".city option").remove();$(".city").append("<option value=0>==请选择==</option>");for(var i=0;i<city.length;i++){$(".city").append("<option value="+city[i].id+">"+city[i].city+"</option>");}});});  $(".city").change(function(){  if($(".city").val()==0){  $(".town option").remove();  $(".town").append("<option value=0>==请选择==</option>");  return;  } mydwr.findTownById($(this).val(),function(town){$(".town option").remove();$(".town").append("<option value=0>==请选择==</option>");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:

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

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

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

dao类

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;          }      }  }

web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list>    <!-- DWR -->  <servlet>  <servlet-name>dwr_invoker</servlet-name>  <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>  <init-param>  <param-name>debug</param-name>  <param-value>true</param-value>  </init-param>   <init-param>             <param-name>crossDomainSessionSecurity</param-name>             <param-value>false</param-value>      </init-param>      <init-param>            <param-name>allowScriptTagRemoting</param-name>            <param-value>true</param-value>      </init-param>    </servlet>  <servlet-mapping>  <servlet-name>dwr_invoker</servlet-name>  <url-pattern>/dwr/*</url-pattern>  </servlet-mapping></web-app>

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