how to construct an instance of BasicTableModelWrap to render a Tableview

[王文楠]

I get resultset base on JdbcTemplate  in spring

here is my sourcecode
////////////////////////////////////////////////////////////////////////////////////////////////////////////
public class JdbcPageTableModel implements IBasicTableModel {
..........
   public Iterator getCurrentPageRows(int nFirst, int nPageSize,
ITableColumn arg2,
           boolean arg3) {
       List list = new JdbcTemplate(dataSource).queryForList("select
login_name,password from user_info ");
       for(int i=0;i<list.size();i++){
           Map map = (Map)list.get(i);
           System.out.println("============"+map.get("login_name"));
       }
       return list.iterator();
   }
....................

}
public abstract class StockDetail extends BasePage{
................................
   public ITableModel getMyTableModel(){
       Object[] columns =
       {
       "user_name","user name","user_name",new Boolean(false)
       ,"password","password","password",new Boolean(false)
       };
       ExpressionTableColumnModel columnModel = new
ExpressionTableColumnModel(columns,new ExpressionEvaluatorImpl());
           return new
BasicTableModelWrap(getJdbcPageTableModel(),columnModel);
       }
...........................................
}

StockDetail.html
 <span jwcid="[EMAIL PROTECTED]:TableView"
            tableModel="ognl:myTableModel"
             pageSize="ognl:10">
     <table width="800" border="1">
       <tr>
         <td height="24" bgcolor="#FCA632" align="center"
jwcid="@Contrib:TableColumns"></td>
       </tr>
       <tr jwcid="[EMAIL PROTECTED]:TableRows">
         <td bgcolor="#FFF1E1" height="24" align="center"
jwcid="@Contrib:TableValues">&nbsp;</td>
       </tr>
     </table>
    <table width ="100%"><tr><td align="center">
        <span jwcid="@Contrib:TableFormPages" pagesDisplayed="ognl:10"/>
   </td></tr></table>
</span>

///////////////////////////////////////////////////////////////////////////////////
the system can print out
"=============Green"
"==============John"
but the page StockDetail just display the title row of the table and other
rows with no content


the system print errors like this:
ERROR org.apache.tapestry.contrib.table.model.ognl.OgnlTableColumnEvaluator
- Cannot use column expression 'password' in row
java.lang.NullPointerException
   at org.apache.tapestry.services.impl.ExpressionEvaluatorImpl.read(
ExpressionEvaluatorImpl.java:82)
   at
org.apache.tapestry.contrib.table.model.ognl.OgnlTableColumnEvaluator.getColumnValue
(OgnlTableColumnEvaluator.java:56)
   at
org.apache.tapestry.contrib.table.model.simple.SimpleTableColumn.getColumnValue
(SimpleTableColumn.java:208

what is my wrong