包括Netbeans中的本地库

Question

我正在尝试从java签名的applet中读取便携式设备....我在http://code.google.com/p/jmtp/w/list上找到了一个jmtp库 来访问便携式设备,但是当我运行它时netbeans它给出了错误

    Exception in thread "main" java.lang.UnsatisfiedLinkError: no jmtp in java.library.path
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1860)
        at java.lang.Runtime.loadLibrary0(Runtime.java:845)
        at java.lang.System.loadLibrary(System.java:1084)
        at jmtp.PortableDeviceManagerImplWin32.(PortableDeviceManagerImplWin32.java:38)
        at jmtp.PortableDeviceManager.(PortableDeviceManager.java:34)
        at jmtp.Jmtp.main(Jmtp.java:23)
    Java Result: 1
    

我搜索并发现我必须在.jmtp项目中包含.dll文件作为本机库...我右键单击项目并导航到属性,然后选择"运行"和选择的VM选项为

-Djava.library.path="c:\jmtp\native\windows"

并将该jmtp.dll文件放在c:\ jmtp文件夹中

但是我的代码不断出现同样的错误

    package jmtp;


import jmtp.PortableDevice;
import jmtp.PortableDeviceManager;
import jmtp.PortableDeviceObject;
import jmtp.PortableDeviceStorageObject;

public class Jmtp {

    public static void main(String[] args) {
        PortableDeviceManager manager = new PortableDeviceManager();
        PortableDevice device = manager.getDevices()[0]; 

        // Connect to my mp3-player
        device.open();
        System.out.println(device.getModel());
        System.out.println("---------------");

        // Iterate over deviceObjects
        for(PortableDeviceObject object : device.getRootObjects()) {

            // If the object is a storage object
            if(object instanceof PortableDeviceStorageObject) {
                PortableDeviceStorageObject storage = (PortableDeviceStorageObject)object;

                for(PortableDeviceObject o2 :  storage.getChildObjects()){
                    System.out.println(o2.getName());
                 }              
            }
        }
        manager.getDevices()[0].close();

    }
}


 

拜托,告诉我是什么问题

    

Answer 1

最后我找到了解决方案,为了包含本机库,我们需要在netbeans中添加以下步骤

     ==>Right click on the Project
     ==>Properties
     ==>Click on RUN
     ==>VM Options : -Djava.library.path="C:\Your Directory where Dll is present"
     ==>Ok
    

Answer 2

您还可以使用以下行从程序中加载库:

System.loadLibrary("jmtp")

将包含该文件的文件夹jmtp.dll直接放在Java项目下.

或者,我尝试了这个,它的工作原理:

System.setProperty( "java.library.path", "libs" );

而"libs"是包含dll的文件夹,直接放在java项目文件夹下.

我注意到jmtp.dll使用64位JDK给出以下异常:

Exception in thread "main" java.lang.UnsatisfiedLinkError: libs/jmtp (.\libs/jmtp.dll is not a valid Win32 application. )
    at java.lang.ClassLoader.loadLibraryWithPath(ClassLoader.java:1018)
    at java.lang.ClassLoader.loadLibraryWithClassLoader(ClassLoader.java:982)
    at java.lang.System.loadLibrary(System.java:506)
    at podcasts.Transferer.main(Transferer.java:28)

您需要在32位JDK上运行该程序才能使其正常工作.