Question

I am working on a java project
I am using jdk 1.6

I am want to add data from database in jtable
I have achieved this by using DefaulTableModel
and I got the column names by using ResultSetMetadata
but the problem is

**I am getting a extra column name A at the 0th index of jtable
I want to remove this column
it looks like this

A | deptno

I only need deptno
**

the code used for creating this model is

private void updateTable() throws Exception {

    String sqlrow = "Select count(*) from emp";
    rs= db.sta.executeQuery(sqlrow); 
        rs.next();                           
     int rows=rs.getInt(1);  
    System.out.println(""+rows);


    String sqldata = "SELECT deptno FROM emp";
   rs =db.sta.executeQuery(sqldata);
    rsMD = rs.getMetaData();
   numberOfColumns = rsMD.getColumnCount();
   ColumnNames = new String[numberOfColumns+1];
    System.out.println(""+numberOfColumns);

    for(int i=1;i<=numberOfColumns;i++)
    {
        String colName=rsMD.getColumnName(i);
        ColumnNames[i] = colName;
        System.out.println(""+ColumnNames[i]);
    }


    //Cj is a method which takes sqlQuery , rows, column
    Object[][] rowData=CJ(sqldata,rows,numberOfColumns);
    //jt is table name 
    jt.setModel(new DefaultTableModel(rowData,ColumnNames));

}

// code for cj()

     public Object[][] CJ(String sql,int rows,int cols)
{
    Object[][] obj=new Object[rows][cols+1];
    ResultSet rs=null;
    try{
         rs= db.sta.executeQuery(sql);
        int c=0;
            while(rs.next())
            {        
            for(int i=1;i<=cols;i++)
                {
                      obj[c][i]=rs.getString(i);                        
                }
                c++;
            }

        }
    catch(Exception ex)
    {
        ex.printStackTrace();
    }
    return obj;
}

I am using this code on
button click

                 updateTable();
            jsp = new JScrollPane(jt); // jt is Jtable
             jp.add(jsp); //jp is jpanel

please help me out

Answer 1

Not following the naming convention makes it hard to read, but I would suggest to take a closer look at the following piece of code

   numberOfColumns = rsMD.getColumnCount();
   ColumnNames = new String[numberOfColumns+1];
    System.out.println(""+numberOfColumns);

    for(int i=1;i<=numberOfColumns;i++)
    {
        String colName=rsMD.getColumnName(i);
        ColumnNames[i] = colName;
        System.out.println(""+ColumnNames[i]);
    }

Here you explicitly use more column names then numberOfColumns. Idem for your CJ method, where you start at index 1.
Just start all those for loops at index 0, make the arrays one shorter and everything should work