Windows，JNA：无法加载本机库-UnsatisfiedLinkError

Question

I am using Java 7 on Windows 7 and am trying to use Java JNA (Java Native Access) (4.2.2) [ link: https://github.com/java-native-access/jna ] to provide access to a C language native library . I have done this on a Linux system and have no problems finding and loading the library.

I am using the suggested technique of setting the system property jna.library.path to the path where the library is located. As mentioned above, this works on Linux, but on Windows I cannot get it to find and load the library.

On the Windows platform, the library comes in both 32 and 64 bit variants (I'm trying to use the 32-bit), with both .lib and .dll files.

I also set the system properties jna.debug_load and jna.debug_load.jna to true as suggested to watch how JNA does its thing.

I have tried the following to no avail:

• System.setProperty("jna.library.path", "C:\\Program Files (x86)\\VMware\\VMware VIX"); ( Windows style path )
• System.setProperty("jna.library.path", "C:/Program Files (x86)/VMware/VMware VIX"); ( UNIX style path )
• I placed the library in a path that has no spaces in it.
• I added the library name on the path (with and without file extension). Eg "C:\\Program Files (x86)\\VMware\\VMware VIX\\VixAllProductsDyn". (VixAllProductsDyn.dll)

When I make an attempt, I can see the debug information on the Java console. Oddly, it tries the exact path to where the library file sits - and yet does not find it .

If anyone has run into this and knows anything about solving the problem, it would be much appreciated.

Trying (via loadLibrary) jnidispatch
Looking in classpath from sun.misc.Launcher$AppClassLoader@1a1a7aa4 for /com/sun/jna/win32-x86-64/jnidispatch.dll
Found library resource at jar:file:/C:/Users/jo24447/.m2/repository/net/java/dev/jna/jna/4.2.2/jna-4.2.2.jar!/com/sun/jna/win32-x86-64/jnidispatch.dll
Trying C:\Users\jo24447\AppData\Local\Temp\jna--734724592\jna8544680981267090708.dll
Found jnidispatch at C:\Users\jo24447\AppData\Local\Temp\jna--734724592\jna8544680981267090708.dll
Looking for library 'VixAllProductsDyn'
Adding paths from jna.library.path: C:\Program Files (x86)\VMware\VMware VIX
Trying C:\Program Files (x86)\VMware\VMware VIX\VixAllProductsDyn.dll
Adding system paths: []
Trying C:\Program Files (x86)\VMware\VMware VIX\VixAllProductsDyn.dll
Looking for lib- prefix
Trying libVixAllProductsDyn.dll
Looking in classpath from sun.misc.Launcher$AppClassLoader@1a1a7aa4 for VixAllProductsDyn
Exception in thread "main" java.lang.UnsatisfiedLinkError: Unable to load library 'VixAllProductsDyn': Native library (win32-x86-64/VixAllProductsDyn.dll) not found in resource path ([file:/C:/Users/jo24447/luna_workspace/VMUtil/vm-util/target/classes/, file:/C:/Users/jo24447/.m2/repository/log4j/log4j/1.2.17/log4j-1.2.17.jar, file:/C:/Users/jo24447/.m2/repository/org/slf4j/slf4j-api/1.7.2/slf4j-api-1.7.2.jar, file:/C:/Users/jo24447/.m2/repository/org/slf4j/slf4j-log4j12/1.7.2/slf4j-log4j12-1.7.2.jar, file:/C:/Users/jo24447/.m2/repository/net/java/dev/jna/jna/4.2.2/jna-4.2.2.jar, file:/C:/Users/jo24447/.m2/repository/net/java/dev/jna/jna-platform/4.2.2/jna-platform-4.2.2.jar])
    at com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:277)
    at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:403)
    at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:342)
    at edu.mit.ll.oms.security.vm.VIXLibrary.<clinit>(VIXLibrary.java:24)
    at edu.mit.ll.oms.security.vm.test.QuickTest.main(QuickTest.java:16)

Answer 1

(1) Try the following:

1. Put both windows (64/32Bit) dlls (and .so's if you wish) into a zip file and rename the file to .jar afterwards.
2. Add that file to your application classpath.
3. Now if your dll is named "VixAllProductsDyn.dll" then call loadLibrary like this: Native.loadLibrary("VixAllProductsDyn","VixAllProductsDyn.class");

(2) Secondly did you try to set the path like this: java -Djava.library.path=c:\\yourLocation VixAllProductsDyn

(3) If you have an applet/webstart application you can specify the native library location with the native lib attribute.

(4) Other than that you may answer the following questions: What architecture (32/64Bit) does your windows system have? What architecture (32/64Bit) does your java have? What version of the dll do you try to run in which case?

Maybe you try an invalid combination of system architecture / JVM and library version...

Update:

Can you share your code? It should look something like this:

VixAllProductsDyn lib = (VixAllProductsDyn) Native.loadLibrary("VixAllProductsDyn", VixAllProductsDyn.class);

The VixAllProductsDyn.java is an interface containing all methods you want to use:

public interface VixAllProductsDyn extends Library {

    public abstract NativeLong OneOfTheMethodsYouWantToCall();
    ...
}

Are you sure that you included all the necessary *.dlls and *.libs etc. which are needed?