在普通Java中，没有可见的Java容器也没有正确的方法，而在Windows中也有焦点，KeyLoggers在Java中被阻止，
（不是主要问题，但也不会打印任何内容）来自util.Timer的循环不在EDT中，更多在Swing的Concurency中，工具包来自AWT软件包，EDT问题也适用于大多数AWT软件包
为我工作（在满足前两点的情况下，..），用于测试目的是尝试在此程序执行期间将焦点移到Windows OS中的另一个活动窗口
码
import java.awt.AWTEvent;import java.awt.EventQueue;import java.awt.Toolkit;import java.awt.event.AWTEventListener;import java.awt.event.ActionEvent;import java.awt.event.KeyEvent;import javax.swing.AbstractAction;import javax.swing.Action;import javax.swing.Jframe;public class ToolkitAndNumLock { private javax.swing.Timer timer = null; private Jframe frame = new Jframe(); public ToolkitAndNumLock() { frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.setSize(400, 300); frame.setVisible(true); start(); //uncomment Toolkit.getXxx listening a KeyEvents, you can (start();) block SwingTimer //Toolkit.getDefaultToolkit().addAWTEventListener(listener, AWTEvent.KEY_EVENT_MASK); } AWTEventListener listener = new AWTEventListener() { @Override public void eventDispatched(AWTEvent event) { if (event instanceof KeyEvent) { KeyEvent ke = (KeyEvent) event; if (ke.getID() == KeyEvent.KEY_PRESSED) { if (ke.getKeyCode() == KeyEvent.VK_CAPS_LOCK) { System.out.println("CapsLock Pressed"); } if (ke.getKeyCode() == KeyEvent.VK_SCROLL_LOCK) { System.out.println("ScrollLock Pressed"); } if (ke.getKeyCode() == KeyEvent.VK_NUM_LOCK) { System.out.println("NumLock Pressed"); } } } } }; private void start() { timer = new javax.swing.Timer(2500, updateCol()); timer.setRepeats(true); timer.start(); } public Action updateCol() { return new AbstractAction("text load action") { private static final long serialVersionUID = 1L; private Boolean bol = true; @Override public void actionPerformed(ActionEvent e) { if (Toolkit.getDefaultToolkit().getLockingKeyState(KeyEvent.VK_NUM_LOCK)) { System.out.println("true"); } else { System.out.println("false"); } if (bol) { Toolkit.getDefaultToolkit().setLockingKeyState(KeyEvent.VK_NUM_LOCK, true); } else { Toolkit.getDefaultToolkit().setLockingKeyState(KeyEvent.VK_NUM_LOCK, false); } bol = !bol; } }; } public static void main(String args[]) { Runnable runner = new Runnable() { @Override public void run() { new ToolkitAndNumLock(); } }; EventQueue.invokeLater(runner); }}
