Re: I can not get data from Table cell

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer,comp.lang.java.help
Date:
Mon, 24 Sep 2007 17:37:18 -0400
Message-ID:
<vrCdnWpbk5KTs2XbnZ2dnUVZ_jydnZ2d@comcast.com>
sahm wrote:

I can not get data from Table cell

...

I try to get String from cell in jTable


Andrew Thompson wrote:

Unless you mean JTable, I do not know the class
you are referring to, and if you *are* referring to
JTable, please take care to use the correct
capitalisation.


sahm wrote:

every time I try to get data from cell I only get null
and this is my code


Andrew Thompson wrote:

* <http://www.physci.org/codes/sscce.html>


sahm wrote:

Class.forName("com.mysql.jdbc.Driver");


You only need to load the class once, not every time you make a connection.

Connection con;
con = DriverManager.getConnection("jdbc:mysql://localhost/uni","root","java");


Why not
  Connection con =
   DriverManager.getConnection( "jdbc:mysql://localhost/uni", "root", "java" );
?

Statement stat = con.createStatement();
ResultSet result;
result = stat.executeQuery("select max(no) from student_info_table");


Why not
  ResultSet result =
   stat.executeQuery( "select max(no) from student_info_table" );
?

result.next();


Ingo R. Homann wrote:

Are you sure, result.next() returns true?

int mx, c;
mx = result.getInt(1);
mx = mx +1;


You set mx to a value, then increment it separately instead of in one
statement, and you don't ever set a value for c.

String inserting_Data = "insert into fee_part_table (feeNO, feeParts,
fee_1st_part) values(?, ?, ?)";
PreparedStatement ps = null;
ps = con.prepareStatement(inserting_Data);


Why initialize ps then immediately discard the initial value?

ps.setInt(1, mx);
ps.setInt(2, c);


c was never set.

String st;
st = String.valueOf(jTable2.getValueAt(0, 0));


Why not
  String st = String.valueOf( jTable2.getValueAt(0, 0) );
?

JOptionPane.showMessageDialog(this, st);


Intermingling GUI and DB code like this is not good structure. You should
also be sure that GUI code runs on the Event Dispatch Thread (EDT) and that
the database code does not.

ps.setString(3, String.valueOf(jTable2.getValueAt(0, 0)));
ps.executeUpdate();


Roedy Green said:

... you posted this twice independently. This splits the discussion.
Don't do this. See

<http://mindprod.com/jgloss/multiposting.html>

Andrew Thompson wrote:

These are code snippets. They do not even compile here,
let alone display the problem. Perhaps if you prepared an
SSCCE* and copy/pasted the first 10-20 lines of the Exception
Stacktrace that occurs, you would have a better chance of
being helped.

* <http://www.physci.org/codes/sscce.html>


--
Lew

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