java限制文本框可输入的最多字符数，java文本框,import java.

java限制文本框可输入的最多字符数，java文本框,import java.

import java.awt.*;import java.awt.event.*;public class TextFieldWithLimit extends TextField    implements KeyListener {   private int  maxLength;   public TextFieldWithLimit           (String initialStr,int col,int maxLength) {     super(initialStr,col);     this.maxLength = maxLength;     addKeyListener(this);     }   public TextFieldWithLimit (int col,int maxLength) {     this("",col,maxLength);     }   public void keyPressed(KeyEvent e) {     char c = e.getKeyChar();    int len = getText().length();    if (len < maxLength) {      return;      }    else {      if((c==KeyEvent.VK_BACK_SPACE)||        (c==KeyEvent.VK_DELETE) ||        (c==KeyEvent.VK_ENTER)||         (c==KeyEvent.VK_TAB)||         e.isActionKey())         return;      else {         e.consume();          }      }   }   public void keyReleased(KeyEvent e) { }   public void keyTyped(KeyEvent e) { }   }