Thread: how to do validation using java swing?

Hi, This is the real code, database name is kics , table name is dateframe and fields are date, style, description, fabricgsm, agegroup, size, measurementsunits..

Here i want to validate componentTextField, TFstyle, TFdescription, TFfabricGSM, TFagegroup, TFsize, TFmeasurements; if these fields are null or left blank and click the save button, i must get the message box as "XYZ(date,style....) field should be entered".

public class dateFrame extends JFrame { 
 
JTextField componentTextField = new JTextField(); 
JTextField TFstyle; 
JTextField TFdescription; 
JTextField TFfabricGSM; 
JTextField TFagegroup; 
JTextField TFsize; 
JTextField TFmeasurements; 
 
public static void main(String[] args) { 
dateFrame df = new dateFrame(); 
} 
 
public dateFrame() { 
super("Date Frame"); 
dateFramePanel dfp = new dateFramePanel(); 
save s = new save(); 
getContentPane().add(dfp, BorderLayout.PAGE_START); 
getContentPane().add(s, BorderLayout.SOUTH); 
pack(); 
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
setLocation(350, 250); 
setResizable(false); 
setVisible(true); 
} 
 
class dateFramePanel extends JPanel { 
 
DateChooser dc = new DateChooser(); 
 
public dateFramePanel() { 
super(new GridLayout(0, 2)); 
JLabel Ldate = new JLabel("Date"); 
JLabel Lstyle = new JLabel("Style"); 
JLabel Ldescription = new JLabel("Description"); 
JLabel LfabricGSM = new JLabel("Fabric & GSM"); 
JLabel Lagegroup = new JLabel("Age group"); 
JLabel Lsize = new JLabel("Size"); 
JLabel Lmeasurements = new JLabel("Measurement units (CM / INCH)"); 
 
TFstyle = new JTextField(10); 
TFdescription = new JTextField(10); 
TFfabricGSM = new JTextField(10); 
TFagegroup = new JTextField(10); 
TFsize = new JTextField(10); 
TFmeasurements = new JTextField(10); 
 
add(Ldate); 
add(dc); 
add(Lstyle); 
add(TFstyle); 
add(Ldescription); 
add(TFdescription); 
add(LfabricGSM); 
add(TFfabricGSM); 
add(Lagegroup); 
add(TFagegroup); 
add(Lsize); 
add(TFsize); 
add(Lmeasurements); 
add(TFmeasurements); 
 
setPreferredSize(new Dimension(700, 200)); 
} 
} 
 
class save extends JPanel { 
 
public save() { 
JButton save = new JButton("Save"); 
add(save); 
save.addActionListener(new JDBC()); 
} 
}

class JDBC implements ActionListener { 
 
public void actionPerformed(ActionEvent e) { 
Connection con = null; 
Statement stmt; 
String loadDriver = "sun.jdbc.odbc.JdbcOdbcDriver"; 
try { 
Class.forName(loadDriver); 
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/kics", "root", ""); 
stmt = con.createStatement(); 
String exe = "insert into kics.dateframe(date,style,description,fabricgsm,agegroup,size,measurementsunits)values('" + componentTextField.getText() + "', 
 
'"+ TFstyle.getText() + "','" + TFdescription.getText() + "','" + TFfabricGSM.getText() + "','" + TFagegroup.getText() + "','"+ TFsize.getText() + "', 
 
'"+ TFmeasurements.getText() + "')"; 
 
stmt.executeUpdate(exe); 
 
 
} catch (Exception e1) { 
System.out.println("Exception found"); 
System.err.println(e1.getMessage()); 
} finally { 
try { 
con.close(); 
} catch (Exception e1) { 
System.out.println("Exception found"); 
System.err.print(e1.getMessage()); 
} 
} 
} 
}

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.*;
import javax.swing.*;
 
public class ValidationDemo extends JFrame  implements ActionListener{
    JTextField tfName,tfCity;
    JButton btnSave;
 
    JPanel con;
 
	public ValidationDemo(String name){
	    super(name);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setSize(400,400);
 
		tfName = new JTextField(20);
		tfCity = new JTextField(20);
		btnSave = new JButton("Save");
		btnSave.addActionListener(this);
 
		con = new JPanel();
		add(con);
		con.add(tfName);
		con.add(tfCity);
		con.add(btnSave);
 
 
        setVisible(true);
	}
 
	public void actionPerformed(ActionEvent ae){
 
 
		if(ae.getSource()==btnSave){
			if(isBlank(tfName))
				showMessage(tfName,"Please enter name");
			else if(isBlank(tfCity))
				showMessage(tfCity,"Please enter City");
 
                       //here you can add more else if conditions for other text fields.
 
		}
	}
 
	public boolean isBlank(JTextField tf){
           //	this is to check if text field is blank
 
			if(tf.getText().trim().equals("")){
				return true;
			}
			return false;
	}
 
	//This function is to show error message and set focus to the box which is empty
 
	public void showMessage(JTextField tf , String msg){
			JOptionPane.showMessageDialog(null,msg);
			tf.requestFocus();
	}
 
    public static void main(String[] args) {
		new ValidationDemo("Validation Demo");
    }
 
 
 
 
}

Please feel free to contact if any problem in understanding the code.