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.java
package 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>