Как вызвать метод C (API-интерфейса сканера) с помощью java с помощью JNI

Question

У меня есть API-интерфейс сканера, который содержит DLL (LsApi.dll), и я должен использовать его методы с JAVA с помощью JNI. Я попытался использовать первый метод (LSConnect), который возвращает целое число LS_OKAY, если устройство правильно подключено или LS_PERIPHERAL_NOT_FOUND, если нет, и, к сожалению, я всегда получаю ошибки.

это мой код в Java:

public class Scanner { 

public final static short LS_515_USB = 502; 
private static final short hconnect = 0; 
public final int LS_OKAY = 0; 

public native static int LSConnect(int hWnd, int hlnst, short Peripheral, 
     short hConnect); 

static { 
    System.loadLibrary("lsApi"); 
} 

/** 
* @param args 
*/ 
public static void main(String[] args) { 
    new Scanner(); 
    System.out.println("connexion établie: " 
      + Scanner.LSConnect(0, 0, LS_515_USB, hconnect)); 

} 

}

и это пример C# определен всех методов:

C# определяет

имен WindowsApplication1

{

public partial class Form1 : Form 

{  



    // from lsapi.h 

    [DllImport(@"lsapi.dll")] 

    internal extern static int LSConnect(int hWnd, int hInst, short Peripheral,ref short hConnect); 



    [DllImport(@"lsapi.dll")] 

    internal extern static int LSDisconnect (short hConnect,int hWnd); 


    [DllImport(@"lsapi.dll")] 

    internal extern static int LSSaveJPEG(int hwnd, int hImage,int quality, string filename); 



    [DllImport(@"lsapi.dll")] 

    internal extern static int LSSaveDIB(int hWnd, int hImage, string filename); 


    // Parameter Type peripheral 

    public const short LS_5xx_SCSI =   500; 

    public const short LS_515_USB  =   502; 

    public const short LS_800_USB  =   801; 



    // ------------------------------------------------------------------------ 

    //       REPLY-CODE 

    // ------------------------------------------------------------------------ 



    public const int     LS_OKAY              =      0; 



    // ------------------------------------------------------------------------ 

    //     ERRORS 

    // ------------------------------------------------------------------------ 

    public const int     LS_SYSTEM_ERROR          =      -1; 

    public const int     LS_USB_ERROR            =      -2; 

    public const int     LS_PERIPHERAL_NOT_FOUND      =      -3; 

    public const int     LS_HARDWARE_ERROR         =      -4; 

    public const int     LS_PERIPHERAL_OFF_ON        =      -5; 

    public const int     LS_RESERVED_ERROR         =      -6; 

    public const int     LS_BOURRAGE            =      -7; 

    public const int     LS_PAPER_JAM            =      -7; 

    public const int     LS_TARGET_BUSY           =      -8; 

    public const int     LS_INVALID_COMMAND         =      -9; 

    public const int     LS_DATA_LOST            =      -10; 

    public const int     LS_COMMAND_IN_EXECUTION_YET    =      -11; 

    public const int     LS_JPEG_ERROR           =      -12; 

    public const int     LS_COMMAND_SEQUENCE_ERROR    =      -13; 

    public const int     LS_PC_HW_ERROR          =      -14; 

    public const int     LS_IMAGE_OVERWRITE         =      -15; 

    public const int     LS_INVALID_HANDLE          =      -16; 

    public const int     LS_NO_LIBRARY_LOAD         =      -17; 

    public const int     LS_BMP_ERROR            =      -18; 

    public const int     LS_TIFF_ERROR            =      -19; 

    public const int     LS_IMAGE_NO_MORE_AVAILABLE     =      -20; 

    public const int     LS_IMAGE_NO_FILMED         =      -21; 

    public const int     LS_IMAGE_NOT_PRESENT        =      -22; 

    public const int     LS_FUNCTION_NOT_AVAILABLE      =      -23; 

    public const int     LS_DOCUMENT_NOT_SUPPORTED     =      -24; 

    public const int     LS_BARCODE_ERROR      =      -25; 

    public const int     LS_INVALID_LIBRARY          =      -26; 

    public const int     LS_INVALID_IMAGE          =      -27; 

    public const int     LS_INVALID_IMAGE_FORMAT    =      -28; 

    public const int     LS_INVALID_BARCODE_TYPE   =      -29; 

    public const int     LS_OPEN_NOT_DONE       =      -30; 

    public const int     LS_INVALID_TYPE_COMMAND      =      -31; 

    public const int     LS_INVALID_CLEARBLACK        =      -32; 

    public const int     LS_INVALID_SIDE           =      -33; 

    public const int     LS_MISSING_IMAGE          =      -34; 

    public const int     LS_INVALID_TYPE           =      -35; 

    public const int     LS_INVALID_SAVEMODE        =      -36; 

    public const int     LS_INVALID_PAGE_NUMBER       =      -37; 

    public const int     LS_INVALID_NRIMAGE         =      -38; 

    public const int     LS_INVALID_STAMP          =      -39; 

    public const int     LS_INVALID_WAITTIMEOUT       =      -40; 

    public const int     LS_INVALID_VALIDATE         =      -41; 

    public const int     LS_INVALID_CODELINE_TYPE      =      -42; 

    public const int     LS_MISSING_NRIMAGE         =      -43; 

    public const int     LS_INVALID_SCANMODE        =      -44; 

    public const int     LS_INVALID_BEEP           =      -45; 

    public const int     LS_INVALID_FEEDER          =      -46; 

    public const int     LS_INVALID_SORTER          =      -47; 

    public const int     LS_INVALID_BADGE_TRACK       =      -48; 

    public const int     LS_MISSING_FILENAME         =      -49; 

    public const int     LS_INVALID_QUALITY          =      -50; 

    public const int     LS_INVALID_FILEFORMAT        =      -51; 

    public const int     LS_INVALID_COORDINATE        =      -52; 

    public const int     LS_MISSING_HANDLE_VARIABLE     =      -53; 

    public const int     LS_INVALID_POLO_FILTER        =      -54; 

    public const int     LS_INVALID_ORIGIN_MEASURES     =      -55; 

    public const int     LS_INVALID_SIZEH_VALUE        =      -56; 

    public const int     LS_INVALID_FORMAT          =      -57; 

    public const int     LS_STRINGS_TOO_LONGS        =      -58; 

    public const int     LS_READ_IMAGE_FAILED        =      -59; 

    public const int     LS_INVALID_CMD_HISTORY       =      -60; 

    public const int     LS_MISSING_BUFFER_HISTORY      =      -61; 

    public const int     LS_INVALID_ANSWER         =      -62; 

    public const int     LS_OPEN_FILE_ERROR_OR_NOT_FOUND  =      -63; 

    public const int     LS_READ_TIMEOUT_EXPIRED   =      -64; 

    public const int     LS_INVALID_METHOD          =      -65; 

    public const int     LS_CALIBRATION_FAILED        =      -66; 

    public const int     LS_INVALID_SAVEIMAGE        =      -67; 

    public const int     LS_INVALID_UNIT           =      -68; 

    public const int     LS_INVALID_NRWINDOWS        =      -71; 

    public const int     LS_INVALID_VALUE          =      -72; 

    public const int     LS_ILLEGAL_REQUEST         =      -73; 

    public const int     LS_INVALID_NR_CRITERIA        =      -74; 

    public const int     LS_MISSING_CRITERIA_STRUCTURE =      -75; 

    public const int     LS_INVALID_MOVEMENT        =      -76; 

    public const int     LS_INVALID_DEGREE          =      -77; 

    public const int     LS_R0TATE_ERROR          =      -78; 

    public const int     LS_MICR_VALUE_OUT_OF_RANGE     =      -79; 

    public const int     LS_PERIPHERAL_RESERVED       =      -80; 

    public const int     LS_INVALID_NCHANGE         =      -81; 

    public const int     LS_BRIGHTNESS_ERROR        =      -82; 

    public const int     LS_CONTRAST_ERROR         =      -83; 

    public const int     LS_INVALID_SIDETOPRINT        =      -84; 

    public const int     LS_DOUBLE_LEAFING_ERROR      =      -85; 

    public const int     LS_INVALID_BADGE_TIMEOUT      =      -86; 

    public const int     LS_INVALID_RESET_TYPE        =      -87; 

    public const int     LS_MISSING_SET_CALLBACK    =      -88; 

    public const int     LS_IMAGE_NOT_200_DPI        =      -89; 

    public const int     LS_DOWNLOAD_ERROR         =      -90; 

    public const int     LS_INVALID_SORT_ON_CHOICE      =      -91; 

    public const int     LS_INVALID_FONT           =      -92; 

    public const int     LS_INVALID_UNIT_SPEED        =      -93; 

    public const int     LS_INVALID_LENGTH          =      -94; 



    public const int     LS_SCAN_NETTO_IMAGE_NOT_SUPPORTED=      -521; 

    public const int     LS_256_GRAY_NOT_SUPPORTED     =      -522; 

    public const int     LS_INVALID_PATH           =      -523; 

    public const int     LS_MISSING_CALLBACK_FUNCTION    =      -526; 

    public const int     LS_INVALID_OCR_IMAGE_SIDE      =      -558; 

    public const int     LS_PERIPHERAL_NOT_ANSWER     =      -599; 



    public const int     LS_INVALID_CONNECTION_HANDLE    =      -1000; 

    public const int     LS_INVALID_CONNECT_PERIPHERAL =      -1001; 

    public const int     LS_PERIPHERAL_NOT_YET_INTEGRATE   =      -1002; 

    public const int     LS_UNKNOW_PERIPHERAL_REPLY    =      -1003; 

Answer 1

Вы не можете вызвать .dll прямо через JNI, просто вызвав LoadLibrary и определяя собственный метод (в отличие от C#). Вам нужно будет написать библиотеку «bridge» (отдельную .dll) в C, которая обертывает lsapi.dll и преобразует соглашения о вызове JNI в соглашения о вызовах lsapi.

Я настоятельно рекомендую использовать JNA вместо написания собственной JNI DLL. Вызов DLL с использованием JNA довольно близок к тривиальным. Есть много ресурсов в Интернете, чтобы помочь, и поиск Java + JNA в stackoverflow даст много помощи.