CODEWITHSUNDEEP
javasqlswingjdbcjtextfield
ViaTras ViaTras
ViaTras ViaTras

Reputation: 31

Display the result of a query in a JTextField's value

I want to display the new id from database in a jTextField but it dosen't.. this is my code

public void actionPerformed(ActionEvent e)  {

    try {
        DB con=new DB();
        con.connecte();

        String req = "SELECT Max(num) FROM condidat";
        ResultSet rs = stmt.executeQuery(req);
        int num = rs.getInt("num");
        int nvNum=num+1;
        txt_num.setText(valueOf(nvNum));

        } 
        catch (ClassNotFoundException ex) {
            Logger.getLogger(Ajouter.class.getName()).log(Level.SEVERE, null, ex);
        } 
        catch (SQLException ex) {
            Logger.getLogger(Ajouter.class.getName()).log(Level.SEVERE, null, ex);
        }

    }
    //To change body of generated methods, choose Tools | Templates.

}

Upvotes: 0

Views: 2261

Answers (2)

hadi
hadi

Reputation: 1

change your integer value to a string because jTextField display only text this way: txt_num.setText(Integer.toString(nvNum));

Upvotes: 0

uraimo
uraimo

Reputation: 19821

You don't call ResultSet.next() and the column in the ResultSet will not be called num but Max(num), if you want a better name, change your query/code this way using AS in your query:

String req = "SELECT Max(num) AS maxnum FROM condidat";
ResultSet rs = stmt.executeQuery(req);
if (rs.next()) {
   int num = rs.getInt("maxnum");
   ...
}

Remember that the ResultSet starts pointing before the first record, so next() must always be called at least one time (and this can also be useful to verify that there is actual data, it will return false if there are no more records). After that if, the ResultSet is ready to be used and it points to the first record.

Edit:

Since it looks like the actionPerformed is not even called, did you register this class as a listener to some JComponent, for example a button?

JButton b = new Button("Click me");
b.addActionListener(this);

If you click this button, and all this code is in the same class, the actionPerformed will be called.

Upvotes: 2

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