如何解决错误消息线程“ main”中的异常java.lang.NoClassDefFoundError：org / usb4java / Loader

Question

I'm trying to make use of usb4java and am getting a error when I run it. It compiles just fine and I have looked at my class path and it appears the usb4java jars are being included as you can see below.

I'm currently on Windows 7, running Java 8, using usb4java-javax-1.2.0( http://usb4java.org/ ). And I'm getting the following error. Any ideas on how to get past this?

"C:\Program Files\Java\jdk1.8.0\bin\java" -Didea.launcher.port=7532 "-Didea.launcher.bin.path=C:\Program Files (x86)\JetBrains\IntelliJ IDEA 13.1.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\rt.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0\jre\lib\ext\zipfs.jar;C:\Users\kim\IdeaProjects\USB_Test_Usb4Java\out\production\USB_Test_Usb4Java;C:\Users\kim\Downloads\usb4java-javax-1.2.0\lib\usb-api-1.0.2.jar;C:\Users\kim\Downloads\usb4java-javax-1.2.0\lib\usb4java-javax-1.2.0.jar;C:\Users\kim\IdeaProjects\USB_Test_Usb4Java\src\usb-api-1.0.2.jar;C:\Users\kim\IdeaProjects\USB_Test_Usb4Java\src\usb4java-javax-1.2.0.jar;C:\Program Files (x86)\JetBrains\IntelliJ IDEA 13.1.1\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain Main
Exception in thread "main" java.lang.NoClassDefFoundError: org/usb4java/Loader
    at org.usb4java.javax.Services.<init>(Services.java:59)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
    at java.lang.Class.newInstance(Class.java:433)
    at javax.usb.UsbHostManager.createUsbServices(Unknown Source)
    at javax.usb.UsbHostManager.getUsbServices(Unknown Source)
    at Main.main(Main.java:89)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: java.lang.ClassNotFoundException: org.usb4java.Loader
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 14 more

Process finished with exit code 1

My Java code looks like this and is copied from the usb4java site.

import javax.usb.UsbConfiguration;
import javax.usb.UsbDevice;
import javax.usb.UsbEndpoint;
import javax.usb.UsbException;
import javax.usb.UsbHostManager;
import javax.usb.UsbHub;
import javax.usb.UsbInterface;
import javax.usb.UsbPort;
import javax.usb.UsbServices;
import java.util.List;

public class Main {

    /**
     * Dumps the specified USB device to stdout.
     *
     * @param device
     *            The USB device to dump.
     */
    private static void dumpDevice(final UsbDevice device)
    {
        // Dump information about the device itself
        System.out.println(device);
        final UsbPort port = device.getParentUsbPort();
        if (port != null)
        {
            System.out.println("Connected to port: " + port.getPortNumber());
            System.out.println("Parent: " + port.getUsbHub());
        }

        // Dump device descriptor
        System.out.println(device.getUsbDeviceDescriptor());

        // Process all configurations
        for (UsbConfiguration configuration: (List<UsbConfiguration>) device
                .getUsbConfigurations())
        {
            // Dump configuration descriptor
            System.out.println(configuration.getUsbConfigurationDescriptor());

            // Process all interfaces
            for (UsbInterface iface: (List<UsbInterface>) configuration
                    .getUsbInterfaces())
            {
                // Dump the interface descriptor
                System.out.println(iface.getUsbInterfaceDescriptor());

                // Process all endpoints
                for (UsbEndpoint endpoint: (List<UsbEndpoint>) iface
                        .getUsbEndpoints())
                {
                    // Dump the endpoint descriptor
                    System.out.println(endpoint.getUsbEndpointDescriptor());
                }
            }
        }

        System.out.println();

        // Dump child devices if device is a hub
        if (device.isUsbHub())
        {
            final UsbHub hub = (UsbHub) device;
            for (UsbDevice child: (List<UsbDevice>) hub.getAttachedUsbDevices())
            {
                dumpDevice(child);
            }
        }
    }

    /**
     * Main method.
     *
     * @param args
     *            Command-line arguments (Ignored)
     * @throws UsbException
     *             When an USB error was reported which wasn't handled by this
     *             program itself.
     */
    public static void main(final String[] args) throws UsbException
    {

        // Get the USB services and dump information about them
        final UsbServices services = UsbHostManager.getUsbServices();
        System.out.println("USB Service Implementation: "
                + services.getImpDescription());
        System.out.println("Implementation version: "
                + services.getImpVersion());
        System.out.println("Service API version: " + services.getApiVersion());
        System.out.println();

        // Dump the root USB hub
        dumpDevice(services.getRootUsbHub());
    }
}

Answer 1

您还需要包含usb4java-1.2.0.jar。