用c标签，el表达式动态取数据库中的值并显示在页面上，动态下拉列表的实现，html:select
首先jsp头部要引个东西，上次因为没引，找了好半天的错误<%@ taglib uri="/tags/c" prefix="c" %>
还有有
<%@ page language="java" pageEncoding="gbk" import="java.util.List,struts.form.KK_BlacklistVehicle_UserEnrolForm"%>
jsp里写的
<% List listCode=bean.KK_BlacklistVehicle_UserEnrolSQLBean.getInstance().diffListCode();//从后台把值取出并放在list里 request.setAttribute("listCode", listCode); %> <% //这个是测试这个list在后台有没有取到值 //for(int i = 0; i < listCode.size(); i++) { //KK_BlacklistVehicle_UserEnrolForm bean = (KK_BlacklistVehicle_UserEnrolForm)listCode.get(i); //System.out.println("页面上输出的：======="+bean.getKk_BlacklistVehicle_UserEnrol_DW()); //} %> <c:if test="${empty listCode}">//这个判断listCode的值有没有传到页面上来，没有的话会在页面上输出not get list value<%out.print("not get list value"); %> </c:if><html:select property="kk_BlacklistVehicle_UserEnrol_DW" > <html:option value="">--请选择单位--</html:option> <c:forEach var="listCode" items="${listCode}">//这句是遍历这个listCode，遍历一次取一次值，赋给 var="listCode" <html:option value="${listCode.kk_BlacklistVehicle_UserEnrol_DW}">${listCode.kk_BlacklistVehicle_UserEnrol_DW}</html:option>//显示出来遍历后的值 </c:forEach> </html:select>KK_BlacklistVehicle_UserEnrolSQLBean
public class KK_BlacklistVehicle_UserEnrolSQLBean{ // 声明一个数据库操作对象 PreparedStatement pstmt = null ; // 声明一个结果集对象 ResultSet rs = null ; // DataBaseConnection为具体的数据库连接及关闭操作类,连接数据库 DataBaseConnection dbc= new DataBaseConnection() ; //数据库对象 Statement sta = null ; private static KK_BlacklistVehicle_UserEnrolSQLBean instance;public synchronized static KK_BlacklistVehicle_UserEnrolSQLBean getInstance() {if(instance==null){ instance=new KK_BlacklistVehicle_UserEnrolSQLBean();}return instance; }publicList diffListCode( ) { DataBaseConnection dbc=new DataBaseConnection(); Connection conn=dbc.getConnection(); PreparedStatement pst = null;List<KK_BlacklistVehicle_UserEnrolForm> list=new ArrayList<KK_BlacklistVehicle_UserEnrolForm>(); String sql="select distinct dw from kk.KKYH "; try { pst = conn.prepareStatement(sql); ResultSet rs=pst.executeQuery(); while(rs.next()) { KK_BlacklistVehicle_UserEnrolForm userEnrolForm=new KK_BlacklistVehicle_UserEnrolForm(); userEnrolForm.setKk_BlacklistVehicle_UserEnrol_DW(rs.getString(1)); list.add(userEnrolForm); } }catch (SQLException e) { e.printStackTrace(); }finally{ try { if(pst!=null) { pst.close(); }if(conn!=null) { conn.close(); } } catch (Exception e) { } }return list; }}
黑色头发 http://heisetoufa.iteye.com
页:
[1]