自定义文本

import javax.swing.JTextField;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.PlainDocument;

public class MyTextField extends JTextField {
	private static final long serialVersionUID = 7207876514583701774L;

	protected Document createDefaultModel() {
		return new NumDocument();
	}

	static class NumDocument extends PlainDocument {
		private static final long serialVersionUID = 6967641956153612767L;

		public void insertString(int offs, String str, AttributeSet a)
				throws BadLocationException {

			if (str == null) {
				return;
			}
			char[] upper = str.toCharArray();
			for (int i = 0; i < upper.length; i++) {
				if (!Character.isDigit(upper[i])) {
					if (!"-".equals(String.valueOf(upper[i]))) {
						str = str.substring(0, i);
					}
				}
			}
			super.insertString(offs, str, a);
		}
	}
}