java – 用JNA单击鼠标

public class App {

public static final int WM_LBUTTONUP = 514;
public static final int WM_LBUTTONDOWN = 513;
public static final int WM_LBUTTONDBLCLK = 0x203;
static int WM_CLOSE = 0x10;
final static String winTitle = "Untitled - Notepad";

public static void main(String[] args) throws InterruptedException {
    User32Extra user32 = (User32Extra) Native.loadLibrary("user32",User32Extra.class,W32APIOptions.DEFAULT_OPTIONS);

    WinDef.HWND hwnd = user32.FindWindow(null,winTitle);
    user32.SetForegroundWindow(hwnd);
    Thread.sleep(1000);

    long y = 77 + (22 << 16);//x + (y << 16)
    WinDef.LPARAM l = new WinDef.LPARAM(y);
    WinDef.WPARAM w = new WinDef.WPARAM(0);
    user32.PostMessage(hwnd,WM_LBUTTONDOWN,w,l);
    Thread.sleep(1000);
    user32.PostMessage(hwnd,WM_LBUTTONUP,l);
}
}

它找到窗户并把它带到前面.但鼠标单击不起作用.也发送WM_CLOSE工作.
鼠标点击有什么问题？
测试计算器和记事本.
坐标是相对于窗口的.