下拉联动

SelectProvAction.java

package com.xxx.hjw.action;

import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

import com.opensymphony.xwork2.ActionSupport;
import com.xxx.hco.HcoFactory;
import com.xxx.hco.entity.HbtRegionEntity;

public class SelectProvAction extends ActionSupport{
	private static final long serialVersionUID = 1L;

	/**
	 * dom4j生成XML文件
	 * @param id
	 * @return
	 */
	
	public String getProv(){
		HttpServletRequest request = ServletActionContext.getRequest();
		HttpServletResponse response = ServletActionContext.getResponse();
		response.setContentType("text/xml;charset=UTF-8");
			Map<Integer,String> map = new HashMap<Integer,String>();
			List<HbtRegionEntity> list = HcoFactory.getHbtRegionRemote().findListById(Integer.valueOf(request.getParameter("regionId")));
			for(HbtRegionEntity  hre :  list){
				map.put(hre.getRegionId(), hre.getNAME());
			}
			Document doc = DocumentHelper.createDocument();
			Element rootElt = doc.addElement("items");
			for (Iterator<Map.Entry<Integer, String>> iter=map.entrySet().iterator(); iter.hasNext();) {
				Map.Entry<Integer, String> entry = iter.next();
				Element itemElt = rootElt.addElement("item");
				Element idElt = itemElt.addElement("id");
				idElt.setText(String.valueOf(entry.getKey()));
				Element nameElt = itemElt.addElement("name");
				nameElt.setText(entry.getValue());
			}
			String xmlString = doc.asXML();
			//System.out.println(xmlString);
			try {
			response.getWriter().write(xmlString);
			} catch (IOException e) {
				e.printStackTrace();
			}
			return null;
	}

}

页面js

<script type="text/javascript">
		function selectProv(field) {
			var xmlHttp = null;
				//表示当前浏览器不是ie,如ns,firefox
				if(window.XMLHttpRequest) {
					xmlHttp = new XMLHttpRequest();
				} else if (window.ActiveXObject) {
					xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
				}
				var url = "private/hbhjw/selectProv.action?regionId=" + field.value + "&time=" + new Date().getTime();
				//设置请求方式为GET，设置请求的URL，设置为异步提交
				xmlHttp.open("GET", url, true);
				
				xmlHttp.onreadystatechange=function() {
					//Ajax引擎状态为成功
					if (xmlHttp.readyState == 4) {
						//HTTP协议状态为成功
						
						if (xmlHttp.status == 200) {
							var doc = xmlHttp.responseXML;
							var items = doc.getElementsByTagName("item");
							//取得省下拉列表
							var provSelect = document.getElementById("statUnitCode");
							//清除省下拉列表中的值
							provSelect.options.length = 0;
							var o = new Option("=选择区=", 0);
							provSelect.add(o);
							for (var i=0; i<items.length; i++) {
								//var id = items[i].childNodes[0].childNodes[0].nodeValue;
								//var name = items[i].childNodes[1].childNodes[0].nodeValue;
								var id = items[i].childNodes[0].firstChild.nodeValue;
								var name = items[i].childNodes[1].firstChild.nodeValue;
								//alert(id + "," + name);
								//构造下拉列表的Option对象
								var o = new Option(name, id);
								//向下拉列表中添加选项
								provSelect.add(o);
							}
						}else {
							alert("请求失败，错误码=" + xmlHttp.status);
						}
					}
				};
				
				//将设置信息发送到Ajax引擎
				xmlHttp.send(null);
			}
		</script>