Validating strings

Question

Hey, how would i go about validating that a JTextField holds a string that doesn't contain any numbers or blank spaces? Obviously you would access the string using 'JTextField'.getText() but how would you parse through the letters to validate it?

Answer 1

Heres the full code I'm working with. It's a GUI character creater and I need to validate the Name field, like I said it can't have numbers, blank spaces, or generally be null.
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.IllegalFormatException;
import javax.swing.*;
public class CharacterCreator extends JFrame {
    JButton CreateButton, ExitButton;
    JPanel MainPanel, ButtonPanel, Center, TextPanel, DropBox, RadioPanel, CheckBoxPanel, NamePanel, LevelPanel;
    JLabel TextArea, job, gender, level, heroic, name;
    JTextField textField1, textField2;
    String textCheck, textCheck1, textCheck2;
    JComboBox box;
    ButtonGroup buttonGroup;
    JCheckBox checkBox;
    JRadioButton button1, button2;
    int intCheck;
    public CharacterCreator(){
        this.setTitle("War Quest Character Creator");
        this.setSize(500, 400);
        this.setLocation(100, 100);
        this.addWindowListener(new ExitListener());
        CreateButton = new JButton("Create");
        CreateButton.addActionListener(new CreateListener());
        ExitButton = new JButton("Exit");
        ExitButton.addActionListener(new ExitListener());
        TextArea = new JLabel();
        TextArea.setSize(500,500);
        JPanel TextPanel = new JPanel(new FlowLayout());
        TextPanel.add(TextArea);
        JPanel ButtonPanel = new JPanel(new FlowLayout());
        ButtonPanel.add(CreateButton);
        ButtonPanel.add(ExitButton);
        JPanel Center = new JPanel();
        Center.setLayout(new BoxLayout(Center, BoxLayout.Y_AXIS ));
        Center.add(createNamePanel());
        Center.add(createComboBoxPanel());
        Center.add(createLevelPanel());
        Center.add(createRadioPanel());
        Center.add(createCheckPanel());
        JPanel MainPanel = new JPanel(new BorderLayout());
        MainPanel.add(ButtonPanel, BorderLayout.SOUTH);
        MainPanel.add(TextPanel, BorderLayout.NORTH);
        MainPanel.add(Center, BorderLayout.CENTER);
        this.setContentPane(MainPanel);
    private JPanel createLevelPanel(){
        textField1 = new JTextField();
        textField1.setEditable(true);
        textField1.setText("Enter Level");
        level = new JLabel("Level:");
        JPanel textFieldPanel = new JPanel();
        textFieldPanel.add(level);
        textFieldPanel.add(textField1);
        return textFieldPanel;
    private JPanel createNamePanel(){
        textField2 = new JTextField();
        textField2.setEditable(true);
        textField2.setText("Enter Name");
        name = new JLabel("Name:");
        JPanel textFieldPanel1 = new JPanel();
        textFieldPanel1.add(name);
        textFieldPanel1.add(textField2);
        return textFieldPanel1;
    private JPanel createCheckPanel(){
        checkBox = new JCheckBox();
        heroic = new JLabel("Heroic:");
        JPanel checkboxPanel = new JPanel();
        checkboxPanel.add(heroic);
        checkboxPanel.add(checkBox);
        return checkboxPanel;
    private JPanel createRadioPanel(){
        button1 = new JRadioButton("Male");
        button1.setSelected(true);
        button2 = new JRadioButton("Female");
        buttonGroup = new ButtonGroup();
        buttonGroup.add(button1);
        buttonGroup.add(button2);
        gender = new JLabel("Gender:");
        JPanel radioButtonPanel = new JPanel();
        radioButtonPanel.add(gender);
        radioButtonPanel.add(button1);
        radioButtonPanel.add(button2);
        return radioButtonPanel;
    private JPanel createComboBoxPanel() {
        String[] options = new String[3];
        options[0]="Barbarian";
        options[1]="Rogue";
        options[2]="Archer";
        box = new JComboBox(options);
        box.setEditable(false);
        box.setEnabled(true);
        box.setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
        box.getInputContext();
        job = new JLabel("Job:");
        JPanel comboBoxPanel = new JPanel();
        comboBoxPanel.add(job);
        comboBoxPanel.add(box);
        return comboBoxPanel;
    public void create(){
     textCheck1 = textField1.getText();
     try{
       intCheck = Integer.parseInt(textCheck1);
     catch(IllegalArgumentException nfe) {
       System.out.println("NumberFormatException: Level must be a number between 1-70");
       return;
     if(intCheck>70){
         throw new NumberFormatException("NumberFormatException: Level must be a number between 1-70");
     else{
       TextArea.setText("Character Successfully Created");
       if(button1.isSelected()){
       System.out.println("Character: \n"+"Name: "+textField2.getText()+"\n"+"Job: "+box.getSelectedItem()+"\n"+"Level: "+textField1.getText()+"\n"+"Gender: Male"+"\n"+"Heroic: "+checkBox.isSelected()+"\n");
       else if(button2.isSelected()){
       System.out.println("Character: \n"+"Name: "+textField2.getText()+"\n"+"Job: "+box.getSelectedItem()+"\n"+"Level: "+textField1.getText()+"\n"+"Gender: Male"+"\n"+"Heroic: "+checkBox.isSelected()+"\n");
    private void exit() {
        System.exit(0);
    private class ExitListener extends WindowAdapter implements ActionListener {
        public void windowClosing(WindowEvent e) {
            exit();
         public void actionPerformed(ActionEvent e) {
            exit();
    private class CreateListener extends WindowAdapter implements ActionListener {
         public void actionPerformed(ActionEvent e) {
            create();
    public static void main(String[] args) {
        CharacterCreator character = new CharacterCreator();
        character.setVisible(true);
} If I were to use a JFormatedTextField instead of a regular one, how would I then format the field? The sub-methods and Javadoc on the sun site don't make a lot of sense as a Java beginner. The way I originally though about doing this was by nesting another loop in the create() method that would parse the string and check for numbers or spaces but I couldn't figgure out how to do that either. If someone could help I'd appreciate it. Thanks.