最近研究一下ajax和<html>互動 ^_^ 感覺還真是不錯
首先創建兩個實體類 get set方法
國家
public class Country implements Serializable{
private static final Long serialVersionUID=123456789098765432L;
private Long id;
private String name;
private Set<City> city=new HashSet<City>(0);
城市
public class City implements Serializable{
private static final long serialVersionUID=-250998437593347316L;
private Long id;
private String name;
private Country country;
一對多關係 持久層 用hibernate 這裏就不多說了
兩個類要和ActionForm放在同個包下
ActionForm
public class RegisterForm extends ActionForm {
/**
*
*/
private Country country=new Country();
public Collection<Country> getCountrys(){
List<Country> list=new ArrayList<Country>();
Show show=new ShowImpl();
list=show.show();
return list;
}
}
然後是action了
public class OpentionAction extends MappingDispatchAction {
public ActionForward toAjax(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {
RegisterForm reForm=(RegisterForm)form;
return mapping.findForward("toAjax");
}
還有servlet
public class SelectServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
public SelectServlet()
{
super();
}
public void destroy()
{
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
// response.setCharacterEncoding("GBK");
response.setContentType("text/xml");
response.setHeader("Cache-Control", "no-cache");
request.setCharacterEncoding("GBK");
response.setCharacterEncoding("UTF-8");
String targetId =request.getParameter("id").toString();
System.out.println("haha"+targetId);
// 獲得請求中參數爲id的值
String xml_start = "<selects>";
String xml_end = "</selects>";
String xml = "";
Show show=new ShowImpl();
List<City> list1=show.show2();
Iterator it1=list1.iterator();
while(it1.hasNext()){
City city=(City)it1.next();
System.out.println("haha"+city.getCountry().getId().toString());
if(city.getCountry().getId().toString().equalsIgnoreCase(targetId)){
xml +="<select><value>"+city.getId()+"</value><text>"+city.getName()+"</text></select>";
}
}
if (targetId.endsWith("0"))
{
xml = "<select><value>0</value><text>請選擇</text></select>";
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
doGet(request, response);
}
public void init() throws ServletException
{
}
}
下面是頁面了index.jsp
中寫一個<a href ="ajax.do">ajax</a>
ajax.jsp
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage=""%>
<%@taglib uri="http://struts.apache.org/tags-html" prefix="html" %>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %>
<html>
<head>
<title>二級菜單聯動演示</title>
<script type="text/javascript">
var req;
window.οnlοad=function()
{//頁面加載時的函數
}
function Change_Select(){//當第一個下拉框的選項發生改變時調用該函數
var province = document.getElementById('country.name').value;
var url = "select?id="+ escape(province);
if(window.XMLHttpRequest){
req = new XMLHttpRequest();
}else if(window.ActiveXObject){
req = new ActiveXObject("Microsoft.XMLHTTP");
}
if(req){
req.open("GET",url,true);
//指定回調函數爲callback
req.onreadystatechange = callback;
req.send(null);
}
}
//回調函數
function callback(){
if(req.readyState ==4){//4爲返回
if(req.status ==200){//200爲完成
parseMessage();//解析XML文檔
}else{
alert("不能得到描述信息:" + req.statusText);
}
}
}
//解析返回xml的方法
function parseMessage(){
var xmlDoc = req.responseXML.documentElement;//獲得返回的XML文檔
var xSel = xmlDoc.getElementsByTagName('select');
//獲得XML文檔中的所有<select>標記
var select_root = document.getElementById('city');
//獲得網頁中的第二個下拉框
select_root.options.length=0;
//每次獲得新的數據的時候先把每二個下拉框架的長度清0
for(var i=0;i<xSel.length;i++){
var xValue = xSel[i].childNodes[0].firstChild.nodeValue;
//獲得每個<select>標記中的第一個標記的值,也就是<value>標記的值
var xText = xSel[i].childNodes[1].firstChild.nodeValue;
//獲得每個<select>標記中的第二個標記的值,也就是<text>標記的值
var option = new Option(xText, xValue);
//根據每組value和text標記的值創建一個option對象
try{
select_root.add(option);//將option對象添加到第二個下拉框中
}catch(e){
}
}
}
</script>
</head>
<body>
<div align="center">
<html:form>
<table width="70%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td align="center">
二級聯動示例
</td>
</tr>
<tr>
<td>
<html:select property="country.name" οnchange="Change_Select()">
<option value="0">
請選擇
</option>
<html:optionsCollection property="countrys" label="name" value="id" />
</html:select>
<select name="city" id="city">
<!--第二個下拉菜單-->
<option value="0">
請選擇
</option>
</select>
</td>
</tr>
<tr>
<td>
</td>
<tr>
</table>
</html:form>
</div>
</body>
</html>
<struts-config>
<form-beans>
<form-bean name="registerForm" type="form.RegisterForm"/>
</form-beans>
<action-mappings>
<action path="/ajax" type="action.OpentionAction"
name="registerForm" parameter="toAjax" scope="request" >
<forward name="toAjax" path="/ajax.jsp"/>
</action>
</action-mappings>
<!-- message-resources parameter="com.tarena.struts.message.MessageResources"/ -->
</struts-config>
web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<servlet>
<servlet-name>ActionServlet</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet>
<servlet-name>SelectServlet</servlet-name>
<servlet-class>com.SelectServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ActionServlet</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>SelectServlet</servlet-name>
<url-pattern>/select</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
