如何从Action返回数据到页面中的select控件？
现在正做一个小网站，页面中有三个select，分别是select1,select2,select3.根据select1选中的值，传到Action中，然后在数据库中查询到相应的数据(是一个List<String>类型)返回到这个页面，显示在select2中。同样根据select2中选中的值，查询数据库，将结果显示在select3中？我是一个新手，用的是hibernate3.0+Struts 1.2，没有ActionContext类。不想用script在页面中连接数据库。请各位能够详细说一下，贴出代码更好，谢谢！
[解决办法]
可以去了解下类似“省市联动”的例子
[解决办法]
<select name="xxx" id="xxx" value="${xxx}">
<c:forEach items="${users}" var="user">
<option value="${user.getID()}" ${xxx==user.getID()?'selected':''>${user.getUsername()}</option>
</c:forEach>
</select>
users列表应该是你select2的选项，你通过Action把users列表传过来，就可以动态生成选项了吧
[解决办法]
action 先取页面第一个select标签的值 根据这个值找出第二个标签的选项 放到一个list 里面
最后request.setAttribute("users", list) 然后页面按9楼得方法取就行了
[解决办法]
没有用structs，你可以改改
<%@ 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>My JSP 'province.jsp' starting page</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">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script type="text/javascript">
function loadXMLDoc()
{
xmlhttp = null;
var country = document.getElementById("country");
country.length = 1;
country.selectedIndex = 0;
var province = document.getElementById("province");
if(province.value == ""){
return ;
}
varurl="http://localhost:8080/Ajax_Province/GetProvince?&province="+encodeURIComponent(province.value);
if (window.XMLHttpRequest) {// code for Firefox, Mozilla, IE7, etc.
xmlhttp = new XMLHttpRequest();
} else if (window.ActiveXObject) {// code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
if (xmlhttp != null) {
xmlhttp.onreadystatechange = state_Change;
xmlhttp.open("post", url, true);
xmlhttp.send(null);
} else {
alert("Your browser does not support XMLHTTP.");
}
}
function state_Change() {
var province = document.getElementById("province");
var country = document.getElementById("country");
if (xmlhttp.readyState == 4&&xmlhttp.status == 200) {// 4 = "loaded"
var serviceData = xmlhttp.responseText;
if(serviceData == null||serviceData == ""){
return;
}
var s = serviceData.split(",");
for(var i=0;i<s.length-1;i++){
country.options[i+1] = new Option(s[i],s[i]);
}
}
}
</script>
</head>
<body>
出生地:<select id="province" onchange="loadXMLDoc()">
<option value="">------请选择省-----</option>
<option value="江西省">江西省</option>
<option value="江苏省">江苏省</option>
<option value="浙江省">浙江省</option>
<option value="山东省">山东省</option>
<option value="辽宁省">辽宁省</option>
<option value="福建省">福建省</option>
</select>
<select id="country"><option value="">-----请选择市-----</option></select>
</body>
</html>
servlet：
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.neusoft.zjl.service.ProvinceService;
public class GetProvince extends HttpServlet {
/**
* Constructor of the object.
*/
public GetProvince() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
List list = null;
ProvinceService provinceService = new ProvinceService();
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
String strprovince = request.getParameter("province");
if(strprovince == null||"".equals(strprovince)){
return ;
}
String province = new String(strprovince.getBytes("ISO-8859-1"),"UTF-8");
list = provinceService.getCountry(province);//这个是查询数据库的你可以换你的对数据库的操作
if(list ==null){
return;
}
StringBuffer sb = new StringBuffer();
for(int i=0;i<list.size();i++){
String s = (String)list.get(i);
sb.append(s+",");
}
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.print(sb);
out.flush();
out.close();
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
