在JNA中传递参数

问题描述 投票：0回答：1

这段代码填充了一个生成的数据结构SCANNER_FULL_PLUS_EX，然后调用一个函数ScanReadFull_PlusEx()。这两个函数都是由 JNAerator 并应该创建一些文件，如Scan_F.bmp等。

对于 64位java 在windows 10 6-bit上，字节[512]中的文件名不能正确传递给dll。大多数情况下，文件名是 无效

    public short SCANTEST(String fileName) {

        StringBuilder BitmapNameF = new StringBuilder();
        StringBuilder BitmapNameR = new StringBuilder();
        StringBuilder BitmapNameF_IR = new StringBuilder();
        StringBuilder BitmapNameR_IR = new StringBuilder();
        StringBuilder BitmapNameF_UV = new StringBuilder();
        StringBuilder BitmapNameR_UV = new StringBuilder();

        SCANNER_FULL_PLUS_EX m_ScanFullPlusEx = new SCANNER_FULL_PLUS_EX();

        m_ScanFullPlusEx.Version = 0;
        m_ScanFullPlusEx.BrightnessFront = 100;
        m_ScanFullPlusEx.ThresholdFront = 100;
        m_ScanFullPlusEx.BrightnessRear = 100;
        m_ScanFullPlusEx.ThresholdRear = 100;
        m_ScanFullPlusEx.BitsPerPixel = 8;
        m_ScanFullPlusEx.ScanMode = 2;

        m_ScanFullPlusEx.ScanModeIR = 0;
        m_ScanFullPlusEx.ScanModeUV = 0;

        m_ScanFullPlusEx.dwImageWidth = 0;
        m_ScanFullPlusEx.dwImageHeight = 0;

        m_ScanFullPlusEx.pImageFront = new NativeLong(0);
        m_ScanFullPlusEx.dwImageSizeFront = 0;
        m_ScanFullPlusEx.pImageRear = new NativeLong(0);
        m_ScanFullPlusEx.dwImageSizeRear = 0;
        m_ScanFullPlusEx.pIR_ImageFront = new NativeLong(0);
        m_ScanFullPlusEx.dwIR_ImageSizeFront = 0;
        m_ScanFullPlusEx.pIR_ImageRear = new NativeLong(0);
        m_ScanFullPlusEx.dwIR_ImageSizeRear = 0;
        m_ScanFullPlusEx.pUV_ImageFront = new NativeLong(0);
        m_ScanFullPlusEx.dwUV_ImageSizeFront = 0;
        m_ScanFullPlusEx.pUV_ImageRear = new NativeLong(0);
        m_ScanFullPlusEx.dwUV_ImageSizeRear = 0;

        BitmapNameF.append(fileName + "F.bmp");
        BitmapNameR.append(fileName + "R.bmp");
        BitmapNameF_IR.append(fileName + "F_IR.bmp");
        BitmapNameR_IR.append(fileName + "R_IR.bmp");
        BitmapNameF_UV.append(fileName + "F_UV.bmp");
        BitmapNameR_UV.append(fileName + "R_UV.bmp");

        m_ScanFullPlusEx.ImageNameRear = Native.toByteArray(BitmapNameR.toString());
        m_ScanFullPlusEx.ImageNameFront = Native.toByteArray(BitmapNameF.toString());
        m_ScanFullPlusEx.IR_ImageNameFront = Native.toByteArray(BitmapNameF_IR.toString());
        m_ScanFullPlusEx.IR_ImageNameRear = Native.toByteArray(BitmapNameR_IR.toString());
        m_ScanFullPlusEx.UV_ImageNameFront = Native.toByteArray(BitmapNameF_UV.toString());
        m_ScanFullPlusEx.UV_ImageNameRear = Native.toByteArray(BitmapNameR_UV.toString());

        // wrap in 512 buffer
        byte[] f1 = new byte[512]; for (int i=0; i<m_ScanFullPlusEx.ImageNameRear.length;i++) f1[i]=m_ScanFullPlusEx.ImageNameRear[i]; m_ScanFullPlusEx.ImageNameRear = f1;
        byte[] f2 = new byte[512]; for (int i=0; i<m_ScanFullPlusEx.ImageNameFront.length;i++) f2[i]=m_ScanFullPlusEx.ImageNameFront[i]; m_ScanFullPlusEx.ImageNameFront = f2;
        byte[] f3 = new byte[512]; for (int i=0; i<m_ScanFullPlusEx.IR_ImageNameFront.length;i++) f3[i]=m_ScanFullPlusEx.IR_ImageNameFront[i]; m_ScanFullPlusEx.IR_ImageNameFront = f3;
        byte[] f4 = new byte[512]; for (int i=0; i<m_ScanFullPlusEx.IR_ImageNameRear.length;i++) f4[i]=m_ScanFullPlusEx.IR_ImageNameRear[i]; m_ScanFullPlusEx.IR_ImageNameRear = f4;
        byte[] f5 = new byte[512]; for (int i=0; i<m_ScanFullPlusEx.UV_ImageNameFront.length;i++) f5[i]=m_ScanFullPlusEx.UV_ImageNameFront[i]; m_ScanFullPlusEx.UV_ImageNameFront = f5;
        byte[] f6 = new byte[512]; for (int i=0; i<m_ScanFullPlusEx.UV_ImageNameRear.length;i++) f6[i]=m_ScanFullPlusEx.UV_ImageNameRear[i]; m_ScanFullPlusEx.UV_ImageNameRear = f6;

        short ret = MB2Library.INSTANCE.ScanReadFull_PlusEx(ByteBuffer.wrap(Native.toByteArray(gPort.Global)), m_ScanFullPlusEx, MB2Library.SCAN_OUTPUT_FORMAT_FILE_BMP);

        return ret;
    }

结构的C头文件。

typedef struct
{
        int Version;
        int BrightnessFront;
        int ThresholdFront;

        int BrightnessRear;
        int ThresholdRear;
        int BitsPerPixel;

        int ScanMode;   // Front/Rear/Front-Rear
        int ScanModeIR; // ( not yet implemented ) IR Front/Rear/Front-Rear
        int ScanModeUV; // ( not yet implemented ) UV Front/Rear/Front-Rear

        DWORD dwImageWidth;
        DWORD dwImageHeight;

        // Front CIS Image
        HANDLE pImageFront;
        DWORD dwImageSizeFront;

        // Rear CIS Image
        HANDLE pImageRear;
        DWORD dwImageSizeRear;

        // Front IR Image
        HANDLE pIR_ImageFront;
        DWORD dwIR_ImageSizeFront;

        // Rear IR Image
        HANDLE pIR_ImageRear;
        DWORD dwIR_ImageSizeRear;

        // Front UV Image
        HANDLE pUV_ImageFront;
        DWORD dwUV_ImageSizeFront;

        // Rear UV Image
        HANDLE pUV_ImageRear;
        DWORD dwUV_ImageSizeRear;

        // images path
        TCHAR ImageNameFront[512];
        TCHAR ImageNameRear[512];
        TCHAR IR_ImageNameFront[512];
        TCHAR IR_ImageNameRear[512];
        TCHAR UV_ImageNameFront[512];
        TCHAR UV_ImageNameRear[512];

} SCANNER_FULL_PLUS_EX;

typedef SCANNER_FULL_PLUS_EX *PSCANNER_FULL_PLUS_EX;

编辑1:

package mb2;

import java.util.StringTokenizer;

import java.util.Arrays;
import java.util.List;

import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.NativeLibrary;
import com.sun.jna.NativeLong;
import com.sun.jna.Pointer;
import com.sun.jna.Structure;
import com.sun.jna.ptr.ByReference;
import com.sun.jna.ptr.PointerByReference;
import com.sun.jna.ptr.IntByReference;
import com.sun.jna.ptr.ByteByReference;
import com.sun.jna.ptr.DoubleByReference;
import com.sun.jna.ptr.FloatByReference;
import com.sun.jna.ptr.LongByReference;
import com.sun.jna.ptr.NativeLongByReference;
import com.sun.jna.ptr.ShortByReference;

public class SCANNER_FULL_PLUS_EX extends Structure {
    public int Version;
    public int BrightnessFront;
    public int ThresholdFront;
    public int BrightnessRear;
    public int ThresholdRear;
    public int BitsPerPixel;
    /** Front/Rear/Front-Rear */
    public int ScanMode;
    /** ( not yet implemented ) IR Front/Rear/Front-Rear */
    public int ScanModeIR;
    /** ( not yet implemented ) UV Front/Rear/Front-Rear */
    public int ScanModeUV;
    public int dwImageWidth;
    public int dwImageHeight;
    /**
     * Front CIS Image<br>
     * C type : HANDLE
     */
    public NativeLong pImageFront;
    public int dwImageSizeFront;
    /**
     * Rear CIS Image<br>
     * C type : HANDLE
     */
    public NativeLong pImageRear;
    public int dwImageSizeRear;
    /**
     * Front IR Image<br>
     * C type : HANDLE
     */
    public NativeLong pIR_ImageFront;
    public int dwIR_ImageSizeFront;
    /**
     * Rear IR Image<br>
     * C type : HANDLE
     */
    public NativeLong pIR_ImageRear;
    public int dwIR_ImageSizeRear;
    /**
     * Front UV Image<br>
     * C type : HANDLE
     */
    public NativeLong pUV_ImageFront;
    public int dwUV_ImageSizeFront;
    /**
     * Rear UV Image<br>
     * C type : HANDLE
     */
    public NativeLong pUV_ImageRear;
    public int dwUV_ImageSizeRear;
    /**
     * images path<br>
     * C type : TCHAR[512]
     */
    public byte[] ImageNameFront = new byte[512];
    /** C type : TCHAR[512] */
    public byte[] ImageNameRear = new byte[512];
    /** C type : TCHAR[512] */
    public byte[] IR_ImageNameFront = new byte[512];
    /** C type : TCHAR[512] */
    public byte[] IR_ImageNameRear = new byte[512];
    /** C type : TCHAR[512] */
    public byte[] UV_ImageNameFront = new byte[512];
    /** C type : TCHAR[512] */
    public byte[] UV_ImageNameRear = new byte[512];
    public SCANNER_FULL_PLUS_EX() {
        super();
    }
    protected List<String> getFieldOrder() {
        return Arrays.asList("Version", "BrightnessFront", "ThresholdFront", "BrightnessRear", "ThresholdRear", "BitsPerPixel", "ScanMode", "ScanModeIR", "ScanModeUV", "dwImageWidth", "dwImageHeight", "pImageFront", "dwImageSizeFront", "pImageRear", "dwImageSizeRear", "pIR_ImageFront", "dwIR_ImageSizeFront", "pIR_ImageRear", "dwIR_ImageSizeRear", "pUV_ImageFront", "dwUV_ImageSizeFront", "pUV_ImageRear", "dwUV_ImageSizeRear", "ImageNameFront", "ImageNameRear", "IR_ImageNameFront", "IR_ImageNameRear", "UV_ImageNameFront", "UV_ImageNameRear");
    }
    public SCANNER_FULL_PLUS_EX(Pointer peer) {
        super(peer);
    }
    public static class ByReference extends SCANNER_FULL_PLUS_EX implements Structure.ByReference {

    };
    public static class ByValue extends SCANNER_FULL_PLUS_EX implements Structure.ByValue {

    };
}
java jna
1个回答
0
投票

欢迎来到奇妙的世界 字码.

你用的是 Native.toByteArray() 只有 String 参数。 返回

使用getDefaultStringEncoding()返回的编码，返回一个等价于给定字符串的NUL-terminalated字节缓冲区。

当在Strings和字节数组之间转换时，通常不指定编码是一种不好的做法。 在这种情况下，实际上你确实希望使用默认的系统编码，但指定这个编码是很有用的，而且，在这个过程中，你可以了解它在做什么。

默认的 Windows 编码是 UTF-16，它使用 16 位来表示字符 (wchar_t 在C语言中）。) 对于ASCII字符串，比如你正在使用的字符串，这意味着你的字节数组最终以交替的0字节和8位字符字节结束。 (你可以自由地测量你的代码，并输出 Arrays.toString(f1) 自己去看看吧！）。)

C结构使用数组的 TCHAR. 这可以是一个单字节或两个字节，取决于你的编码（这将符合 Native.toByteArray()).

所以这里的默认编码是没有问题的，只是你需要知道这个编码是什么，以便正确地确定结构的大小。 你传递的是512字节的数组，而你可能需要的是512-TCHAR数组（1024字节）。

然而，JNA结构必须知道它们的总字节大小，并且...。TCHAR 在JNA中没有映射。 所以你必须弄清楚 CHAR_WIDTH 并在结构中用该值乘以512。 (搜索JNA源码，可以找到 CHAR_WIDTH 的大量例子。)

(编辑1)

谢谢你提供JNA映射。一般来说，当一个 JNA 映射的函数结构出现错误时，首先要检查的是类型映射。 在您的例子中，除了不正确的 TCHAR 映射到 byte 如上所述，您已经将 HANDLE 作为 NativeLong. 这在Windows上不起作用。HANDLE 在Windows上行不通：从 PointerType 和指针与操作系统位数相匹配，所以在64位Windows上是64位的。 在64位的Windows LONG 另一方面 NativeLong 在Windows上）始终是一个32位类型。

因此，总结一下，你需要（至少）做以下改动。

  1. 改变 HANDLE 类型来映射到JNA的 WinNT.HANDLE 阶层

  2. 更改 TCHAR 字节宽度来匹配字符宽度。 一种方法是在你的类的顶部插入这个（或者在你的项目中的任何地方，公共的，这样它就可以被访问）。

    private static final int CHAR_WIDTH = Boolean.getBoolean("w32.ascii") ? 1 : 2;

然后在你的 byte[] 宣言，乘以 512 * CHAR_WIDTH 以获得正确的宽度。

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