java限制TextField只能输入大写字符，textfield大写,Java[JDK1.1]

java限制TextField只能输入大写字符，textfield大写,Java[JDK1.1]

Java

[JDK1.1]import java.awt.*;import java.awt.event.*;public class UpperTF extends Frame {  public static void main(String argv[]) {    new UpperTF().setVisible(true);  }  public UpperTF() {    setLayout(new FlowLayout());    TextField tf = new TextField(10);    add(tf);      tf.addKeyListener(      new KeyAdapter() {          public void keyPressed(KeyEvent e) {            if (Character.isLetter(e.getKeyChar()))                 e.setModifiers(Event.SHIFT_MASK);             }      });    pack();    addWindowListener(      new WindowAdapter() {          public void windowClosing(WindowEvent e) {            System.exit(0);            }          }    );    }  public Dimension getPreferredSize() {    return new Dimension(200,200);    }}