dwr省市联查

//dwr.xml<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://getahead.org/dwr/dwr20.dtd"><dwr>  <allow>  <!-- create(配置java类,使其在js页面中可以被调用)其中creator表示"通过什么方式获得对象  " javascript表示"对象的名称" param标签中的name表示类型名,value表示"类所在的绝对路径(包+类名)"--> <create creator="new" javascript="dwr">      <param name="class" value="dao.DwrService"/>       </create>    <!-- convert标签配置后,用户可以使用自定义类型的变量(引用类型) -->       <convert converter="bean" match="bean.CityInfo"/>        <convert converter="bean" match="bean.ProvinceInfo"/>  </allow></dwr>//web.xml<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>  </servlet>  <servlet-mapping>    <servlet-name>dwr-invoker</servlet-name>    <url-pattern>/dwr/*</url-pattern> </servlet-mapping>//DwrService.javapackage dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import bean.CityInfo;import bean.ProvinceInfo;import db.DBManager;public class DwrService {  private Connection conn;private PreparedStatement ps;private ResultSet rs;/** * 获取所有省份 * @return */public List<ProvinceInfo> getPro(){return new ProvinceInfoDAO().getPro();}/** *  * @param proId省份编号 * @return 该省的所有城市 */public List<CityInfo> getCity(int proId){return new CityInfoDAO().getCity(proId);}}//jsp页面 function getPro(){    dwr.getPro(function(list){      DWRUtil.addOptions("province",list,'proId','name');    });  }  function getCity(){   //alert(obj.val);  // alert(DWRUtil.getValue("province"));  //或者使用传递对象   dwr.getCity(DWRUtil.getValue("province"),function(list){   DWRUtil.removeAllOptions("city");   DWRUtil.addOptions("city",list,'cityId','cityName');   });  }//form表单部分<select id="province" onchange="getCity()" name="province"><option>--请选择省份--</option></select><select class="input" id="city" name="city"><option>--请选择城市--</option></select>