Regarding JTable

[adeeb]

Hi,
i am not getting the column names at top of the table. Heres the code, i really dont understand the problem. So please help. And also please tell me how to refresh it when i am trying to do the old values are not erased from the table. The new values are added below it.
try
{
conn = DriverManager.getConnection("jdbcdbc:addissue", "library","adeeb");
ps = conn.prepareStatement("SELECT * FROM expired WHERE rollno=?",ResultSet.TYPE_SCROLL_SENSITIVE,ResultSe t.CONCUR_UPDATABLE);
ps.setString(1,ftf.getText().toUpperCase());

String colnames[] = {"ROLLNO","NAME","BOOK","BOOK ID","ISSUED","PRES_DATE","DAYS"};
DefaultTableModel amodel = (DefaultTableModel) tb.getModel();
amodel.setColumnIdentifiers(colnames);
rs=ps.executeQuery();

ResultSetMetaData rsmd = rs.getMetaData();
int colno = rsmd.getColumnCount();
while(rs.next())
{
Object[] row = new Object[colno];
for(int i=0;i<colno;i++)
{
row[i]=rs.getObject(i+1);
}
amodel.addRow(row);
}
tb.setModel(amodel);
tb.revalidate();
}

catch(Exception ce)
{
System.out.println(ce);
}

[Fubarable]

The error is likely in the code that you're not showing us. How do you display the table? Do you simply place it into a JPanel? If so nothing is telling the column names to be drawn. Better to put it into a JScrollPanel, either that or place it into a JPanel BorderLayout.CENTER and place the column headers into the same panel BorderLayout.NORTH.

[adeeb]

Thanks for replying, but see the below code i am unable to add the table to JScrollPane. Now Please Guide me

JButton view = new JButton("View");
JPanel btnp = new JPanel();
btnp.add(view);

view.addActionListener(new ActionListener()
{


public void actionPerformed(ActionEvent e)
{
Vector columnNames = new Vector();
Vector data = new Vector();
try
{
String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
Class.forName( driver );
Connection connection = DriverManager.getConnection( "jdbcdbc:addissue","library", "bismillah" );
//tb.repaint();
String sql = "Select * from expired ORDER BY rollno ASC";
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery( sql );
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();

// Get column names

for (int i = 1; i <= columns; i++)
{
columnNames.addElement( md.getColumnName(i) );
}

// Get row data

while (rs.next())
{
Vector row = new Vector(columns);

for (int i = 1; i <= columns; i++)
{
row.addElement( rs.getObject(i) );
}

data.addElement( row );
}


rs.close();
stmt.close();
JTable tab = new JTable(data, columnNames);
}
catch(Exception ce)
{
System.out.println( ce );
}


}
});

JScrollPane jsp = new JScrollPane(tab);

jp2.setLayout(new BorderLayout());
jp2.add(jsp);
jp2.add(btnp, BorderLayout.SOUTH);

[Eranga]

Since you have use DefaulteTableModel, setModel() can be helpful on the table. I'm not remember the exact way of it. Better to check it on documentation.

[adeeb]

Hi,
thanks very much for all your efforts and help. I have got the table but when i click the button the old records are not erased and the new once are followed by them. I want to get the records freshly. Please see the table code i have used the DefaultTableModel and i cant understand where to add the functions like revalidate() so that i wont face the above problem

code:


JButton view = new JButton("View");
JPanel btnp = new JPanel();
btnp.add(view);
//final JPanel vpanel = new JPanel();
tab = new JTable();
view.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
try
{
conn = DriverManager.getConnection("jdbc dbc:addissue", "library","adeeb");
ps = conn.prepareStatement("SELECT * FROM expired");

String colnames[] = {"ROLLNO","NAME","BOOK","BOOK ID","ISSUED","PRES_DATE","DAYS"};
DefaultTableModel model = (DefaultTableModel) tab.getModel();
model.setColumnIdentifiers(colnames);
rs=ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
int colno = rsmd.getColumnCount();
// ((DefaultTableModel)tab.getModel()).fireTableDataC hanged();
while(rs.next())
{
Object[] row = new Object[colno];
for(int i=0;i<colno;i++)
{
row[i]=rs.getObject(i+1);
}
model.addRow(row);
}
tab.setModel(model);

}

catch(Exception ce)
{
System.out.println(ce);
}

}
});
JScrollPane jsp = new JScrollPane(tab);
jp2.setLayout(new BorderLayout());
jp2.add(jsp);
jp2.add(btnp, BorderLayout.SOUTH);

[Fubarable]

You've posted here long enough that you should know about and start using code tags to allow your code to retain its formatting. No one wants to read unformatted code. To do this you place the tag [code] at the top of your block of code and the tag [/code] at the bottom, like so:

Code:

[code]
  // your code block goes here.
  // note the differences between the tag at the top vs the bottom.
[/code]

[adeeb]

Hi,
thanks very much for all your efforts and help. I have got the table but when i click the button the old records are not erased and the new once are followed by them. I want to get the records freshly. Please see the table code i have used the DefaultTableModel and i cant understand where to add the functions like revalidate() so that i wont face the above problem

Code:

	

		
Code:
	
	
 JButton view = new JButton("View");
JPanel btnp = new JPanel();
btnp.add(view);
//final JPanel vpanel = new JPanel();
tab = new JTable();
view.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
try
{
conn = DriverManager.getConnection("jdbc dbc:addissue", "library","adeeb");
ps = conn.prepareStatement("SELECT * FROM expired");

String colnames[] = {"ROLLNO","NAME","BOOK","BOOK ID","ISSUED","PRES_DATE","DAYS"};
DefaultTableModel model = (DefaultTableModel) tab.getModel();
model.setColumnIdentifiers(colnames);
rs=ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
int colno = rsmd.getColumnCount();
// ((DefaultTableModel)tab.getModel()).fireTableDataC hanged();
while(rs.next())
{
Object[] row = new Object[colno];
for(int i=0;i<colno;i++)
{
row[i]=rs.getObject(i+1);
}
model.addRow(row);
}
tab.setModel(model);

}

catch(Exception ce)
{
System.out.println(ce);
}

}
});
JScrollPane jsp = new JScrollPane(tab);
jp2.setLayout(new BorderLayout());
jp2.add(jsp);
jp2.add(btnp, BorderLayout.SOUTH);

[Fubarable]

you do know that you can use all the code tags in the world, but if your code is not formatted to begin with, the code tags won't work. Should be common sense, no?

[Eranga]

Yes it is. It's much better to format the code in the way that others can read easily. Line spaces, tab spaces and all of stuff make big difference.

Regarding your question, do you know what revalidate() do? Can't you identify the line of the code where start to write data to the table? This is your code though.

[Fubarable]

Interesting reply by Bob Prime in your post in the JavaRanch: Regarding JPanel (Swing / AWT / SWT / JFace forum at JavaRanch)

I hope you take it to heart.

[Eranga]

Same story going on there.

[adeeb]

Hey,
please reply me no. Please give my answer

[Eranga]

Better to check it by yourself, on different locations of data written to the table. I can't test this, because I don't want to add more tables and drivers in my PC and mess.

At least try it just after executing the query.