JNA 如何 載入多個 存在依賴的 DLL 庫，jnadll

JNA 如何 載入多個 存在依賴的 DLL 庫，jnadll

JNA 的出現，極大的簡化了原有的 JNI 技術。下面是JNA github地址：https://github.com/java-native-access/jna

1. 簡單的一個例子：

/** Simple example of JNA interface mapping and usage. */public class HelloWorld {    public interface CLibrary extends Library {        CLibrary INSTANCE = (CLibrary)Native.loadLibrary((Platform.isWindows() ? "msvcrt" : "c"), CLibrary.class);                void printf(String format, Object... args);// void printf(const char *format, [argument]);            }    public static void main(String[] args) {        CLibrary.INSTANCE.printf("Hello, World\n");        for (int i=0; i < args.length; i++) {            CLibrary.INSTANCE.printf("Argument %d: %s\n", i, args[i]);        }    }    }

原理是，通過 CLibrary extends Libarary 在其中載入系統的 DLL/so 庫，並列出Java要調用的DLL庫函數，該函數到DLL庫函數直接的映射有JNA來完成。

這樣就可以調用DLL/so庫中的函數了。

2. 如何使用 JNA 載入多個DLL庫，而且它們之間存在依賴關係

http://stackoverflow.com/questions/32609829/load-multiple-libraries-with-jna

Is there a way in JNA to load multiple libraries with Java?

I usually use Native.loadLibrary(...) to load one DLL. But I guess its not working this way because I assign this function call to the instance member.

Let's say I have library foo and library bar. bar has a dependency on foo; it also has a dependency on baz, which we are not mapping with JNA:

public class Foo {    public static final boolean LOADED;    static {        Native.register("foo");        LOADED = true;    }    public static native void call_foo();}public class Bar {    static {        // Reference "Foo" so that it is loaded first        if (Foo.LOADED) {            System.loadLibrary("baz");            // Or System.load("/path/to/libbaz.so")            Native.register("bar");        }    }    public static native void call_bar();}

The call to System.load/loadLibrary will only be necessary if baz is neither on your library load path (PATH/LD_LIBRARY_PATH, for windows/linux respectively) nor in the same directory as bar(windows only).

EDIT

You can also do this via interface mapping:

public interface Foo extends Library {    Foo INSTANCE = (Foo)Native.loadLibrary("foo");}public interface Bar extends Library {    // Reference Foo prior to instantiating Bar, just be sure    // to reference the Foo class prior to creating the Bar instance    Foo FOO = Foo.INSTANCE;    Bar INSTANCE = (Bar)Native.loadLibrary("bar");}

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3. 自己的代碼例子：

public class DDLTest {public static void main(String[] args){System.out.println(System.getProperty("java.library.path"));FingerLibrary.Fingerdll.ZAZCloseDeviceEx(-1);int r = ID_FprCap.fprCap.LIVESCAN_Init();ID_FprCap.fprCap.LIVESCAN_Close();ID_FprCap.fprCap.LIVESCAN_BeginCapture(1);ID_FprCap.fprCap.LIVESCAN_GetFPRawData(1, "aaaaaa");r = ID_Fpr.INSTANCE.FP_FeatureMatch("aaaaaaaaaaa", "aaaaaaaaaaa", (float)0.5);}public interface FingerLibrary extends Library { int FPDATASIZE = 256; int IMGWIDTH = 256; int IMGHEIGHT = 288; int IMGSIZE = 73728; // 視窗訊息 int WM_FPMESSAGE = 1024 + 120; // 自訂訊息 int FPM_DEVICE = 0x01; // 狀態提示 int FPM_PLACE = 0x02; // 請按手指 int FPM_LIFT = 0x03; // 請抬起手指 int FPM_CAPTURE = 0x04; // 採集映像 int FPM_ENROLL = 0x06; // 登記指紋模版 int FPM_GENCHAR = 0x05; // 採集特徵點 int FPM_NEWIMAGE = 0x07; // 指紋映像 int RET_OK = 0x1; int RET_FAIL = 0x0; FingerLibrary Fingerdll = (FingerLibrary) Native.loadLibrary("ZAZAPIt", FingerLibrary.class); public int ZAZOpenDeviceEx(int[] hHandle, int nDeviceType, int iCom, int iBaud, int nPackageSize, int iDevNum); public int ZAZCloseDeviceEx(int handle); public int ZAZVfyPwd(int pHandle, int nAddr,   byte[] pPassword); public int ZAZReadInfPage(int pHandle, int nAddr,  byte[] pInf);     public int ZAZReadIndexTable(int pHandle, int nAddr, int nPage, byte[] UserContent);       //     public int FP_FeatureMatch(String pFeatureData1, String pFeatureData2, float pfSimilarity);}public interface ID_Fpr extends Library {ID_Fpr INSTANCE  = (ID_Fpr)Native.loadLibrary("ID_Fpr", ID_Fpr.class);//public int LIVESCAN_Init();public int FP_FeatureMatch(String pFeatureData1, String pFeatureData2, float pfSimilarity);//int __stdcall FP_FeatureMatch(unsigned char * pFeatureData1,//輸入參數 指紋特徵資料1//  unsigned char * pFeatureData2,//輸入參數 指紋特徵資料2//  float * pfSimilarity);//輸出參數 匹配相似性值0.00-1.00//typedef int (__stdcall *FP_FeatureMatch)(unsigned char * pFeatureData1,//輸入參數 指紋特徵資料1//  unsigned char * pFeatureData2,//輸入參數 指紋特徵資料2// float * pfSimilarity);//輸出參數 匹配相似性值0.00-1.00}public interface ID_FprCap extends StdCallLibrary {    ID_Fpr fpr = ID_Fpr.INSTANCE ;    ID_FprCap fprCap = (ID_FprCap)Native.loadLibrary("ID_FprCap", ID_FprCap.class);        public int LIVESCAN_Init();//int __stdcall LIVESCAN_Init();    public int LIVESCAN_Close();//int __stdcallLIVESCAN_Close();    public int LIVESCAN_BeginCapture(int nChannel);    public int LIVESCAN_GetFPRawData(int nChannel, String pRawData);//    int__stdcallLIVESCAN_BeginCapture(int nChannel );//    int__stdcallLIVESCAN_GetFPRawData(int nChannel,unsigned char *pRawData);        public int LIVESCAN_GetFPBmpData(int nChannel, String pBmpData);//    int__stdcallLIVESCAN_GetFPBmpData(int nChannel, unsigned char *pBmpData);    public int LIVESCAN_EndCapture(int nChannel);//    int__stdcallLIVESCAN_EndCapture(int nChannel );    public int LIVESCAN_IsSupportSetup();    //    int__stdcallLIVESCAN_IsSupportSetup();    public int LIVESCAN_GetVersion();//    int__stdcallLIVESCAN_GetVersion();    public int LIVESCAN_GetDesc(String pszDesc);//    int__stdcallLIVESCAN_GetDesc(char pszDesc[1024]);    public int LIVESCAN_GetErrorInfo(int nErrorNo, String pszErrorInfo);//    int__stdcallLIVESCAN_GetErrorInfo(int nErrorNo, char pszErrorInfo[256]);    }}