用el表达式取出mysql中的值_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
还有有
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());
//}
%>
//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
--请选择单位--
//这句是遍历这个listCode，遍历一次取一次值，赋给 var="listCode"
${listCode.kk_BlacklistVehicle_UserEnrol_DW}//显示出来遍历后的值
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;
}
public List diffListCode( )
{
DataBaseConnection dbc=new DataBaseConnection();
Connection conn=dbc.getConnection();
PreparedStatement pst = null;
List list=new ArrayList();
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;
}
}
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2008-08-13 20:42
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