JNA 如何 加载多个 存在依赖的 DLL 库

JNA 的出现，极大的简化了原有的 JNI 技术。下面是JNA github地址：https://github.com/java-native-access/jna

1. 简单的一个例子：

/** 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，通过 CLibrary extends Libarary 在其中加载系统的 DLL/so 库，并列出Java要调用的DLL库函数，该函数到DLL库函数直接的映射有JNA来完成。

这样就可以调用DLL/so库中的函数了。

2. 如何使用 JNA 加载多个DLL库，而且它们之间存在依赖关系

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");
}

-----------------

3. 自己的代码例子：

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;

		 // 窗口消息
		 int WM_FPMESSAGE = 1024 + 120; // 自定义消息
		 int FPM_DEVICE = 0x01; // 状态提示
		 int FPM_PLACE = 0x02; // 请按手指
		 int FPM_LIFT = 0x03; // 请抬起手指
		 int FPM_CAPTURE = 0x04; // 采集图像
		 int FPM_ENROLL = 0x06; // 登记指纹模版
		 int FPM_GENCHAR = 0x05; // 采集特征点
		 int FPM_NEWIMAGE = 0x07; // 指纹图像
		 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,	//输入参数 指纹特征数据1
		//		  						unsigned char * pFeatureData2,	//输入参数 指纹特征数据2
		//		  						float * pfSimilarity);			//输出参数 匹配相似度值0.00-1.00

//		typedef int (__stdcall *FP_FeatureMatch)(unsigned char * pFeatureData1,	//输入参数 指纹特征数据1
//			 	 unsigned char * pFeatureData2,	//输入参数 指纹特征数据2
//				 float * pfSimilarity);			//输出参数 匹配相似度值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 __stdcall	LIVESCAN_Close();
	    public int LIVESCAN_BeginCapture(int nChannel);
	    public int LIVESCAN_GetFPRawData(int nChannel, String pRawData);
//	    int		__stdcall	LIVESCAN_BeginCapture(	int nChannel );
//	    int		__stdcall	LIVESCAN_GetFPRawData(int nChannel,unsigned char *pRawData);

	    public int LIVESCAN_GetFPBmpData(int nChannel, String pBmpData);
//	    int		__stdcall	LIVESCAN_GetFPBmpData(int nChannel, unsigned char *pBmpData);

	    public int LIVESCAN_EndCapture(int nChannel);
//	    int		__stdcall	LIVESCAN_EndCapture(int nChannel );

	    public int LIVESCAN_IsSupportSetup();
//	    int		__stdcall	LIVESCAN_IsSupportSetup();

	    public int LIVESCAN_GetVersion();
//	    int		__stdcall	LIVESCAN_GetVersion();

	    public int LIVESCAN_GetDesc(String pszDesc);
//	    int		__stdcall	LIVESCAN_GetDesc(char pszDesc[1024]);

	    public int LIVESCAN_GetErrorInfo(int nErrorNo, String pszErrorInfo);
//	    int		__stdcall	LIVESCAN_GetErrorInfo(int nErrorNo, char pszErrorInfo[256]);
	}
}