Java能不能实现后台键盘监听

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tianlidon
2016-11-14 · TA获得超过1219个赞
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可以实现。
需要到 http://java.net/projects/jna/downloads下载 jna.jar 和 platform.jar (参考http://my.oschina.net/penngo/blog/12356): 
   
package jna_test;
 
import com.sun.jna.platform.win32.*;
import com.sun.jna.platform.win32.WinUser.*;
import com.sun.jna.platform.win32.WinDef.HMODULE;
import com.sun.jna.platform.win32.WinDef.LRESULT;
import com.sun.jna.platform.win32.WinDef.WPARAM;
import com.sun.jna.platform.win32.WinUser.HHOOK;
import com.sun.jna.platform.win32.WinUser.KBDLLHOOKSTRUCT;
import com.sun.jna.platform.win32.WinUser.LowLevelKeyboardProc;
import com.sun.jna.win32.WinUser.Mouse.LowLevelMouseProc;
import com.sun.jna.win32.WinUser.Mouse.MOUSEHOOKSTRUCT;
 
public class MouseLLHook {
    
    // 鼠标钩子函数里判断按键类型的常数
    public static final int WM_LBUTTONUP = 514;
    public static final int WM_LBUTTONDOWN = 513;
    public static final int WM_RBUTTONUP = 517;
    public static final int WM_RBUTTONDOWN = 516;
    public static final int WM_MOUSEHWHEEL = 526;
    public static final int WM_MOUSEWHEEL = 522;
    public static final int WM_MOUSEMOVE = 512;
     
    static HHOOK mouseHHK,keyboardHHK;//鼠标、键盘钩子的句柄
    static LowLevelMouseProc mouseHook;//鼠标钩子函数
    static LowLevelKeyboardProc keyboardHook;//键盘钩子函数
     
    // 安装钩子
    static void setHook() {
        HMODULE hMod = Kernel32.INSTANCE.GetModuleHandle(null);
        mouseHHK = User32.INSTANCE.SetWindowsHookEx(WinUser.WH_MOUSE_LL, mouseHook, hMod, 0);
        keyboardHHK = User32.INSTANCE.SetWindowsHookEx(WinUser.WH_KEYBOARD_LL, keyboardHook, hMod, 0);      
    }
     
    //卸载钩子
    static void unhook() {
        User32.INSTANCE.UnhookWindowsHookEx(keyboardHHK);
        User32.INSTANCE.UnhookWindowsHookEx(mouseHHK);     
    }
     
    public static void main(String[] args) {
         
        keyboardHook = new LowLevelKeyboardProc() {
             
            @Override
            //该函数参数的意思参考:http://msdn.microsoft.com/en-us/library/windows/desktop/ms644985(v=vs.85).aspx
            public LRESULT callback(int nCode, WPARAM wParam, KBDLLHOOKSTRUCT lParam) {
                int w = wParam.intValue();
                //按下alt键时w=.WM_SYSKEYDOWN; 按下其他大部分键时w=WinUser.WM_KEYDOWN
                if(w==WinUser.WM_KEYDOWN || w==WinUser.WM_SYSKEYDOWN)
                    System.out.println("key down: vkCode = "+lParam.vkCode);
                else if(w==WinUser.WM_KEYUP || w==WinUser.WM_SYSKEYUP)
                    System.out.println("key up: vkCode = "+lParam.vkCode);
                 
                // 如果按下'q'退出程序,'q'的vkCode是81
                if(lParam.vkCode==81) {
                    unhook();
                    System.err.println("program terminated.");
                    System.exit(0);
                }
                return User32.INSTANCE.CallNextHookEx(keyboardHHK, nCode, wParam, lParam.getPointer());
            }
        };
         
        mouseHook = new LowLevelMouseProc() {
             
            @Override
            //该函数参数的意思参考:http://msdn.microsoft.com/en-us/library/windows/desktop/ms644986(v=vs.85).aspx
            public LRESULT callback(int nCode, WPARAM wParam, MOUSEHOOKSTRUCT lParam) {
                switch (wParam.intValue()) {
                case WM_MOUSEMOVE:
                    System.out.print("mouse moved:");
                    break;
                case WM_LBUTTONDOWN:
                    System.out.print("mouse left button down:");
                    break;
                case WM_LBUTTONUP:
                    System.out.print("mouse left button up");
                    break;
                case WM_RBUTTONUP:
                    System.out.print("mouse right button up:");
                    break;
                case WM_RBUTTONDOWN:
                    System.out.print("mouse right button down:");
                    break;
                case WM_MOUSEWHEEL:
                    System.out.print("mouse wheel rotated:");
                    break;             
                }
                System.out.println("("+lParam.pt.x+","+lParam.pt.y+")");
                return User32.INSTANCE.CallNextHookEx(mouseHHK, nCode, wParam, lParam.getPointer());
            }
        };
         
        System.out.println("press 'q' to quit.");
        setHook();     
                 
        int result;
        MSG msg = new MSG();
        // 消息循环
        // 实际上while循环一次都不执行,这些代码的作用我理解是让程序在GetMessage函数这里阻塞,不然程序就结束了。
        while ((result = User32.INSTANCE.GetMessage(msg, null, 0, 0)) != 0) {          
            if (result == -1) {
                System.err.println("error in GetMessage");
                unhook();
                break;
            } else {
                User32.INSTANCE.TranslateMessage(msg);               
                User32.INSTANCE.DispatchMessage(msg);
            }
        }
        unhook();
    }   
     
     
}
   
2. [代码]以上代码如果有两个类找不到(不知什么原因,我当时下载的版本就可以),那就只好自己写了:     
   
import com.sun.jna.Structure;
import com.sun.jna.platform.win32.BaseTSD.ULONG_PTR;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinDef.LRESULT;
import com.sun.jna.platform.win32.WinDef.WPARAM;
import com.sun.jna.platform.win32.WinUser.HOOKPROC;
import com.sun.jna.platform.win32.WinUser.POINT;
 
interface LowLevelMouseProc extends HOOKPROC {
    LRESULT callback(int nCode, WPARAM wParam, MOUSEHOOKSTRUCT lParam);
}
 
class MOUSEHOOKSTRUCT extends Structure {
    public class ByReference extends MOUSEHOOKSTRUCT implements
            Structure.ByReference {
    };
 
    public POINT pt;
    public HWND hwnd;
    public int wHitTestCode;
    public ULONG_PTR dwExtraInfo;
}
指拈笺k
2016-11-12 · 超过14用户采纳过TA的回答
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publicclassFrameextendsJFrame{ privateJTextAreaj; publicvoidinit(){ j.addKeyListener(newKeyAdapter(){ @Override publicvoidkeyPressed(KeyEvente){ //当按下W时 if(e.getKeyCode()==KeyEvent.VK_W){ //调用方法 } //当按下J时 if(e.getKeyCode()==KeyEvent.VK_J){ //调用方法 } } }); }}
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