我用谷歌搜索了关于获取连接到 linux OS 的 USB 的信息，发现 USB4JAVA 非常有帮助。我找到了如下示例代码。现在运行它后，我得到了“java.lang.ExceptionInInitializerError”的异常。
我使用的代码：
import org.usb4java.ConfigDescriptor;
import org.usb4java.Context;
import org.usb4java.DescriptorUtils;
import org.usb4java.Device;
import org.usb4java.DeviceDescriptor;
import org.usb4java.DeviceHandle;
import org.usb4java.DeviceList;
import org.usb4java.LibUsb;
import org.usb4java.LibUsbException;
/**
* Dumps the descriptors of all available devices.
*
* @author Klaus Reimer <k@ailis.de>
*/
public class DumpDevices
{
/**
* Dumps all configuration descriptors of the specified device. Because
* libusb descriptors are connected to each other (Configuration descriptor
* references interface descriptors which reference endpoint descriptors)
* dumping a configuration descriptor also dumps all interface and endpoint
* descriptors in this configuration.
*
* @param device
* The USB device.
* @param numConfigurations
* The number of configurations to dump (Read from the device
* descriptor)
*/
public static void dumpConfigurationDescriptors(final Device device,
final int numConfigurations)
{
for (byte i = 0; i < numConfigurations; i += 1)
{
final ConfigDescriptor descriptor = new ConfigDescriptor();
final int result = LibUsb.getConfigDescriptor(device, i, descriptor);
if (result < 0)
{
throw new LibUsbException("Unable to read config descriptor",
result);
}
try
{
System.out.println(descriptor.dump().replaceAll("(?m)^",
" "));
}
finally
{
// Ensure that the config descriptor is freed
LibUsb.freeConfigDescriptor(descriptor);
}
}
}
/**
* Dumps the specified device to stdout.
*
* @param device
* The device to dump.
*/
public static void dumpDevice(final Device device)
{
// Dump device address and bus number
final int address = LibUsb.getDeviceAddress(device);
final int busNumber = LibUsb.getBusNumber(device);
System.out.println(String
.format("Device %03d/%03d", busNumber, address));
// Dump port number if available
final int portNumber = LibUsb.getPortNumber(device);
if (portNumber != 0)
System.out.println("Connected to port: " + portNumber);
// Dump parent device if available
final Device parent = LibUsb.getParent(device);
if (parent != null)
{
final int parentAddress = LibUsb.getDeviceAddress(parent);
final int parentBusNumber = LibUsb.getBusNumber(parent);
System.out.println(String.format("Parent: %03d/%03d",
parentBusNumber, parentAddress));
}
// Dump the device speed
System.out.println("Speed: "
+ DescriptorUtils.getSpeedName(LibUsb.getDeviceSpeed(device)));
// Read the device descriptor
final DeviceDescriptor descriptor = new DeviceDescriptor();
int result = LibUsb.getDeviceDescriptor(device, descriptor);
if (result < 0)
{
throw new LibUsbException("Unable to read device descriptor",
result);
}
// Try to open the device. This may fail because user has no
// permission to communicate with the device. This is not
// important for the dumps, we are just not able to resolve string
// descriptor numbers to strings in the descriptor dumps.
DeviceHandle handle = new DeviceHandle();
result = LibUsb.open(device, handle);
if (result < 0)
{
System.out.println(String.format("Unable to open device: %s. "
+ "Continuing without device handle.",
LibUsb.strError(result)));
handle = null;
}
// Dump the device descriptor
System.out.print(descriptor.dump(handle));
// Dump all configuration descriptors
dumpConfigurationDescriptors(device, descriptor.bNumConfigurations());
// Close the device if it was opened
if (handle != null)
{
LibUsb.close(handle);
}
}
/**
* Main method.
*
* @param args
* Command-line arguments (Ignored)
*/
public static void main(final String[] args)
{
// Create the libusb context
final Context context = new Context();
// Initialize the libusb context
int result = LibUsb.init(context);
if (result < 0)
{
throw new LibUsbException("Unable to initialize libusb", result);
}
// Read the USB device list
final DeviceList list = new DeviceList();
result = LibUsb.getDeviceList(context, list);
if (result < 0)
{
throw new LibUsbException("Unable to get device list", result);
}
try
{
// Iterate over all devices and dump them
for (Device device: list)
{
dumpDevice(device);
}
}
finally
{
// Ensure the allocated device list is freed
LibUsb.freeDeviceList(list, true);
}
// Deinitialize the libusb context
LibUsb.exit(context);
}
}
我得到的例外：
Exception in thread "main" java.lang.ExceptionInInitializerError
at find_usb.DumpDevices.main(DumpDevices.java:132)
Caused by: org.usb4java.LoaderException: Native library not found in classpath: /org/usb4java/linux-x86/libusb4java.so
at org.usb4java.Loader.extractLibrary(Loader.java:281)
at org.usb4java.Loader.load(Loader.java:358)
at org.usb4java.LibUsb.<clinit>(LibUsb.java:640)