32 位 JRE 中的 jna 指针
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【中文标题】32 位 JRE 中的 jna 指针【英文标题】：jna Pointer in 32 bit JRE 【发布时间】：2015-11-09 18:08:36 【问题描述】：我正在使用 jna 在 Java 中调用 Magnification api 函数。
MagImageScalingCallback.java
package jna.extra;
import com.sun.jna.Callback;
import com.sun.jna.Pointer;
import com.sun.jna.platform.win32.WinDef.HRGN;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinDef.RECT;
public interface MagImageScalingCallback extends Callback
public Boolean MagImageScalingCallback(HWND hwnd, Pointer srcdata,MAGIMAGEHEADER srcheader, Pointer destdata,MAGIMAGEHEADER destheader,RECT source,RECT clipped,HRGN dirty);
MAGIMAGEHEADER.java
package jna.extra;
import java.util.Arrays;
import java.util.List;
import com.sun.jna.platform.win32.Guid.GUID;
public class MAGIMAGEHEADER extends com.sun.jna.Structure
public int width;
public int height;
public GUID format;
public int stride;
public int offset;
public int cbsize;
public List getFieldOrder()
return Arrays.asList("width","height","format","stride","offset","cbsize");
Magnification.java
package jna.extra;
import com.sun.jna.Native;
import com.sun.jna.platform.win32.WinDef.DWORD;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinDef.RECT;
import com.sun.jna.win32.StdCallLibrary;
import com.sun.jna.win32.W32APIOptions;
public interface Magnification extends StdCallLibrary
Magnification INSTANCE = (Magnification) Native.loadLibrary("magnification", Magnification.class,
W32APIOptions.DEFAULT_OPTIONS);
public Boolean MagInitialize();
public boolean MagSetWindowFilterList(HWND hwndMag, DWORD dword, int i,
HWND[] excludeHWNDs);
public boolean MagSetWindowSource(HWND hwndMag, RECT sourceRect);
public void MagGetWindowFilterList(HWND hwndMag, DWORD dword, int i, HWND[] test);
public boolean MagSetImageScalingCallback(HWND hwndMag,MagImageScalingCallback MagImageScalingCallback);
public MagImageScalingCallback MagGetImageScalingCallback(HWND hwndMag);
WinGDIExtra.java
package jna.extra;
import com.sun.jna.platform.win32.WinDef.DWORD;
import com.sun.jna.platform.win32.WinGDI;
public interface WinGDIExtra extends WinGDI
public DWORD SRCCOPY = new DWORD(0x00CC0020);
public DWORD SRCPAINT = new DWORD(0x00ee0086);
public DWORD SRCAND = new DWORD(0x008800c6);
public DWORD SRCINVERT = new DWORD(0x00660046);
public DWORD SRCERASE = new DWORD(0x00440328);
public DWORD NOTSRCCOPY = new DWORD(0x00330008);
public DWORD NOTSRCERASE = new DWORD(0x001100a6);
public DWORD MERGECOPY = new DWORD(0x00c000ca);
public DWORD MERGEPAINT = new DWORD(0x00bb0226);
public DWORD PATCOPY = new DWORD(0x00f00021);
public DWORD PATPAINT = new DWORD(0x00fb0a09);
public DWORD PATINVERT = new DWORD(0x005a0049);
public DWORD DSTINVERT = new DWORD(0x00550009);
public DWORD WHITENESS = new DWORD(0x00ff0062);
public DWORD BLACKNESS = new DWORD(0x00000042);
public DWORD CAPTUREBLT = new DWORD(0x00CC0020 | 0x40000000);
public DWORD Black = new DWORD(0x00000000);
public long WS_CHILD = 0x40000000L;
public long WS_VISIBLE = 0x10000000L;
public long MS_SHOWMAGNIFIEDCURSOR = 0x0001L;
public long WS_EX_TOPMOST = 0x00000008L;
public long WS_EX_LAYERED = 0x00080000;
public long WS_EX_TRANSPARENT = 0x00000020L;
public long WS_CLIPCHILDREN = 0x02000000L;
public long MW_FILTERMODE_EXCLUDE = 0;
我的代码
package jna.extra;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import com.sun.jna.platform.win32.Kernel32;
import com.sun.jna.platform.win32.WinDef.DWORD;
import com.sun.jna.platform.win32.WinDef.HRGN;
import com.sun.jna.platform.win32.WinDef.RECT;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import luz.winapi.jna.User32;
public class screenSkip
public static void main(String[] args)
if(!Magnification.INSTANCE.MagInitialize())
System.out.println("Cannot Intialize Magnification API");
System.exit(0);
RECT desktopRect= new RECT();
HWND desktop = User32.INSTANCE.GetDesktopWindow();
if(desktop==null)
System.out.println("Problem with Desktop");
System.exit(0);
if(!User32Extra.INSTANCE.GetWindowRect(desktop, desktopRect))
System.err.println("Cannot get window rect");
System.exit(0);
HWND top = User32Extra.INSTANCE.CreateWindowEx(new DWORD(WinGDIExtra.WS_EX_TOPMOST | WinGDIExtra.WS_EX_LAYERED | WinGDIExtra.WS_EX_TRANSPARENT), "#32770", "Parent Window", new DWORD(WinGDIExtra.WS_CLIPCHILDREN), desktopRect.left, desktopRect.top, desktopRect.right-desktopRect.left, desktopRect.bottom-desktopRect.top, desktop, null, null, null);
if(top==null)
System.out.println("Problem while creating Parent Window and the error is "+Native.getLastError());
System.exit(0);
HWND hwndMag=null;
System.out.println(Native.getLastError());
hwndMag = User32Extra.INSTANCE.CreateWindowEx(null, "Magnifier", "MagWindow", new DWORD(WinGDIExtra.WS_CHILD | WinGDIExtra.MS_SHOWMAGNIFIEDCURSOR | WinGDIExtra.WS_VISIBLE), desktopRect.left, desktopRect.top, desktopRect.right-desktopRect.left, desktopRect.bottom-desktopRect.top, top, null, Kernel32.INSTANCE.GetModuleHandle(null), null);
if(hwndMag==null)
System.err.println("Problem while creating Magnifier Window and the error is "+Native.getLastError());
System.exit(0);
RECT sourceRect= new RECT();
if(!User32Extra.INSTANCE.GetWindowRect(desktop, sourceRect))
System.err.println("Cannot get window rect");
System.exit(0);
final BufferedImage image = new BufferedImage(1366, 768, BufferedImage.TYPE_INT_RGB);
if(!Magnification.INSTANCE.MagSetImageScalingCallback(hwndMag,new MagImageScalingCallback()
public Boolean MagImageScalingCallback(HWND hwnd, Pointer srcdata,
MAGIMAGEHEADER srcheader, Pointer destdata,
MAGIMAGEHEADER destheader, RECT source, RECT clipped, HRGN dirty)
image.setRGB(0, 0, srcheader.width, srcheader.height, srcdata.getIntArray(0, srcheader.width * srcheader.height ), 0, srcheader.width);
return true;
))
System.err.println("Error occured while setting callback");
System.exit(0);
if (!Magnification.INSTANCE.MagSetWindowSource(hwndMag, sourceRect))
System.err.println("Cannot copy");
System.exit(0);
try
ImageIO.write(image, "JPEG", new File("printed1.jpg"));
catch (IOException e)
e.printStackTrace();
if (!Magnification.INSTANCE.MagSetWindowSource(hwndMag, sourceRect))
System.err.println("Cannot copy");
System.exit(0);
如果调用MagSetWindowSource 函数，则调用MagImageScalingCallback 函数。
问题是，如果我使用 jre7（64 位）运行此代码，一切正常。但是如果我在 jre7（32 位）中运行相同的代码，我会收到以下错误。
# # Java 运行时环境检测到一个致命错误： # # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x10002a21, pid=5552, tid=4884 # # JRE 版本：Java(TM) SE 运行时环境 (7.0_80-b15) (build 1.7.0_80-b15) # Java VM：Java HotSpot(TM) Client VM（24.80-b11混合模式，共享windows-x86） # 有问题的框架： #C [jna6797525900717560222.dll+0x2a21] # # 无法写入核心转储。默认情况下，在 Windows 的客户端版本上不启用小型转储 # # 如果您想提交错误报告，请访问： # http://bugreport.java.com/bugreport/crash.jsp # 崩溃发生在 Java 虚拟机之外的本地代码中。 # 查看有问题的框架以了解报告错误的位置。 # 堆栈：[0x05c60000,0x05cb0000]，sp=0x05cae4d0，可用空间=313k 本机帧：（J=编译的 Java 代码，j=解释的，Vv=VM 代码，C=本机代码） C [jna6797525900717560222.dll+0x2a21] j com.sun.jna.Pointer._getInt(J)I+0 j com.sun.jna.Pointer.getInt(J)I+6 j com.sun.jna.Pointer.getValue(JLjava/lang/Class;Ljava/lang/Object;)Ljava/lang/Object;+340 j com.sun.jna.Structure.readField(Lcom/sun/jna/Structure$StructField;)Ljava/lang/Object;+168 j com.sun.jna.Structure.read()V+82 j com.sun.jna.CallbackReference$DefaultCallbackProxy.convertArgument(Ljava/lang/Object;Ljava/lang/Class;)Ljava/lang/Object;+330 j com.sun.jna.CallbackReference$DefaultCallbackProxy.invokeCallback([Ljava/lang/Object;)Ljava/lang/Object;+95 j com.sun.jna.CallbackReference$DefaultCallbackProxy.callback([Ljava/lang/Object;)Ljava/lang/Object;+2 v ~StubRoutines::call_stub V [jvm.dll+0x1429aa] V [jvm.dll+0x20743e] V [jvm.dll+0x142a2d] V [jvm.dll+0xcb7b2] V [jvm.dll+0xcd5df] C [jna6797525900717560222.dll+0x9dd2] C [jna6797525900717560222.dll+0xa47f] C [jna6797525900717560222.dll+0xc864] C [jna6797525900717560222.dll+0xcdee] C 0x00b80012 C [放大.dll+0x5434] C [放大.dll+0x5a2c] C [放大.dll+0x5f5d] C [放大.dll+0x612a] C [放大.dll+0x28ab] C [USER32.dll+0x162fa] C [USER32.dll+0x16d3a] C [USER32.dll+0x1965e] C [USER32.dll+0x196c5] C [放大.dll+0x22e2] C [jna6797525900717560222.dll+0xcc77] C [jna6797525900717560222.dll+0xc78a] C [jna6797525900717560222.dll+0x4561] C [jna6797525900717560222.dll+0x4d2e] j com.sun.jna.Function.invokeInt(I[Ljava/lang/Object;)I+0 j com.sun.jna.Function.invoke([Ljava/lang/Object;Ljava/lang/Class;Z)Ljava/lang/Object;+315 j com.sun.jna.Function.invoke(Ljava/lang/Class;[Ljava/lang/Object;Ljava/util/Map;)Ljava/lang/Object;+214 j com.sun.jna.Library$Handler.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;+341 j com.sun.proxy.$Proxy5.MagSetWindowSource(Lcom/sun/jna/platform/win32/WinDef$HWND;Lcom/sun/jna/platform/win32/WinDef$RECT;)Z+20 j org.redfire.screen.ScreenShare$CaptureScreen.run()V+674 j java.lang.Thread.run()V+11 v ~StubRoutines::call_stub V [jvm.dll+0x1429aa] V [jvm.dll+0x20743e] V [jvm.dll+0x142b75] V [jvm.dll+0x142bd7] V [jvm.dll+0xed5cf] V [jvm.dll+0x163c4c] V [jvm.dll+0x1646a7] V [jvm.dll+0x1a92f9] C [msvcr100.dll+0x5c556] C [msvcr100.dll+0x5c600] C [kernel32.dll+0x133aa] C [ntdll.dll+0x39f72] C [ntdll.dll+0x39f45] Java 框架：（J=编译的 Java 代码，j=解释的，Vv=VM 代码） j com.sun.jna.Pointer._getInt(J)I+0 j com.sun.jna.Pointer.getInt(J)I+6 j com.sun.jna.Pointer.getValue(JLjava/lang/Class;Ljava/lang/Object;)Ljava/lang/Object;+340 j com.sun.jna.Structure.readField(Lcom/sun/jna/Structure$StructField;)Ljava/lang/Object;+168 j com.sun.jna.Structure.read()V+82 j com.sun.jna.CallbackReference$DefaultCallbackProxy.convertArgument(Ljava/lang/Object;Ljava/lang/Class;)Ljava/lang/Object;+330 j com.sun.jna.CallbackReference$DefaultCallbackProxy.invokeCallback([Ljava/lang/Object;)Ljava/lang/Object;+95 j com.sun.jna.CallbackReference$DefaultCallbackProxy.callback([Ljava/lang/Object;)Ljava/lang/Object;+2 v ~StubRoutines::call_stub j com.sun.jna.Function.invokeInt(I[Ljava/lang/Object;)I+0 j com.sun.jna.Function.invoke([Ljava/lang/Object;Ljava/lang/Class;Z)Ljava/lang/Object;+315 j com.sun.jna.Function.invoke(Ljava/lang/Class;[Ljava/lang/Object;Ljava/util/Map;)Ljava/lang/Object;+214 j com.sun.jna.Library$Handler.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;+341 j com.sun.proxy.$Proxy5.MagSetWindowSource(Lcom/sun/jna/platform/win32/WinDef$HWND;Lcom/sun/jna/platform/win32/WinDef$RECT;)Z+20 j org.redfire.screen.ScreenShare$CaptureScreen.run()V+674 j java.lang.Thread.run()V+11 v ~StubRoutines::call_stub如何解决这个问题？如何在 32 位 JRE 上完成这项工作？ 谢谢！
【问题讨论】：
我确定我之前已经对您说过，但您只展示了部分代码。为什么不能显示 MCVE？这样我们就不必猜测了。 @DavidHeffernan 更新问题。 没有。请进行网络搜索以了解 MCVE 的含义。您的更新既不是最小的，也不是完整的。可以编译问题中的代码吗？ 【参考方案1】：首先，MagImageScalingCallback 定义为WINAPI 函数，这意味着您必须将回调定义为StdCallCallback 的子级。
其次，返回类型是一个简单的布尔值（你不应该为此使用布尔值）。
第三，回调的参数是MAGIMAGEHEADER，而不是MAGIMAGEHEADER *，并且RECT不是RECT *，也就是说需要传值；所以回调声明需要像这样改变：
我添加了一个RectByValue 类，包含以下内容：
import com.sun.jna.platform.win32.WinDef;
import com.sun.jna.Structure;
public class RectByValue extends WinDef.RECT implements Structure.ByValue
我用以下内容更改了MagImageScalingCallback 类：
import com.sun.jna.win32.StdCallLibrary;
public interface MagImageScalingCallback extends StdCallLibrary.StdCallCallback
public boolean MagImageScalingCallback(HWND hwnd, Pointer srcdata,MAGIMAGEHEADER.ByValue srcheader, Pointer destdata,MAGIMAGEHEADER.ByValue destheader,RectByValue source,RectByValue clipped,HRGN dirty);
您需要将ByValue 支持添加到MAGIMAGEHEADER；并且还使用SIZE_T 作为结构的最后一个元素：
import java.util.Arrays;
import java.util.List;
import com.sun.jna.platform.win32.Guid.GUID;
import com.sun.jna.platform.win32.BaseTSD;
import com.sun.jna.Pointer;
import com.sun.jna.Structure;
public class MAGIMAGEHEADER extends Structure
public int width;
public int height;
public GUID format;
public int stride;
public int offset;
public BaseTSD.SIZE_T cbsize;
public List getFieldOrder()
return Arrays.asList("width","height","format", "stride","offset","cbsize");
public static class ByValue extends MAGIMAGEHEADER implements Structure.ByValue
public ByValue()
public ByValue(MAGIMAGEHEADER magimageheader)
super (magimageheader.getPointer());
width = magimageheader.width;
height = magimageheader.height;
format = magimageheader.format;
stride = magimageheader.stride;
offset = magimageheader.offset;
cbsize = magimageheader.cbsize;
public ByValue(Pointer memory)
super(memory);
public MAGIMAGEHEADER(Pointer memory)
super(memory);
read();
public MAGIMAGEHEADER()
我更改了屏幕大小以匹配我在screenSkip 上的显示，所以它是new BufferedImage(2160, 1440... 而不是1366, 786，并将回调代码创建者更改为：
if(!Magnification.INSTANCE.MagSetImageScalingCallback(hwndMag, new MagImageScalingCallback()
public boolean MagImageScalingCallback(HWND hwnd, Pointer srcdata,
MAGIMAGEHEADER.ByValue srcheader, Pointer destdata,
MAGIMAGEHEADER.ByValue destheader, RectByValue source, RectByValue clipped, HRGN dirty)
image.setRGB(0, 0, srcheader.width, srcheader.height, srcdata.getIntArray(0, srcheader.width * srcheader.height ), 0, srcheader.width);
return true;
))
System.err.println("Error occured while setting callback");
System.exit(0);
在 32 位或 64 位模式下运行的最终产品是一个名为 这大约是我认为可以实现您想要的最少的。
....呵呵...它给了我一个 32 位的空白图像。这似乎不正确。
【讨论】：
谢谢！我找不到任何StdCallLibrary.StdCallback 接口。所以，我使用了StdCallLibrary.StdCallCallback。但我遇到了同样的错误。
@Mahesh 请为所有相关类（例如 MAGIMAGEHEADER）添加您的定义，因为您可能定义错误。
@Mahesh 需要进行一些更改。我会在答案中解释
@Mahesh 我有你的代码，对CreateWindowEx 稍作改动 - 我使用了User32Util.createWindowEx，并添加了一个实现GetWindowRect 和GetDesktopWindow 的类，只是为了让那些缺失的类正常工作，为 java 7 32bit、java 8 32bit 和 java 8 64bit 生成 .jpg。
@Petesh 你能在答案中添加修改吗？以上是关于32 位 JRE 中的 jna 指针的主要内容，如果未能解决你的问题，请参考以下文章