我尝试通过 usb4java api 从 USB 设备读取，但出现错误：USB 错误 5：无法读取数据：找不到实体有人可以帮助我吗？必须注意的是，endpoint_in 我从 LibUsb.ENDPOINT_IN 获取它并将其传递给读取功能找到的设备已被声明，但我无法继续从设备中读取。
My code is given below:
import java.io.IOException;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;
import javax.swing.JOptionPane;
import org.usb4java.BufferUtils;
import org.usb4java.Context;
import org.usb4java.Device;
import org.usb4java.DeviceDescriptor;
import org.usb4java.DeviceHandle;
import org.usb4java.DeviceList;
import org.usb4java.LibUsb;
import org.usb4java.LibUsbException;
public class Test {
private static byte endpoint;
// private static final byte IN_ENDPOINT = 0;
private static Device device;
private static Context context = new Context();
private static DeviceHandle handle;
public static void main(String[] args) {
// Create the libusb context
LibUsb.init(null);
findDevice(context, (short) (0x046D), (short) (0xC016));
// Deinitialize the libusb context
LibUsb.exit(context);
}
public static void findDevice(Context context, short vendorId, short productId) {
// 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
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 list them
for (Device device : list) {
int address = LibUsb.getDeviceAddress(device);
int busNumber = LibUsb.getBusNumber(device);
DeviceDescriptor descriptor = new DeviceDescriptor();
result = LibUsb.getDeviceDescriptor(device, descriptor);
if (result < 0) {
throw new LibUsbException(
"Unable to read device descriptor", result);
}
System.out.format(
"Bus %03d, Device %03d: Vendor %04x, Product %04x%n",
busNumber, address, descriptor.idVendor(),
descriptor.idProduct());
if (result != LibUsb.SUCCESS) {
throw new LibUsbException("Unable to read device descriptor", result);
}
if (descriptor.idVendor() == vendorId && descriptor.idProduct() == productId) {
System.out.println("Device Found");
getDeviceHandle(device);
LibUsb.claimInterface(handle, 0);
}
}
} finally {
// Ensure the allocated device list is freed
LibUsb.freeDeviceList(list, true);
}
}
public static void getDeviceHandle(Device device) {
endpoint = (byte)LibUsb.getDeviceAddress(device);
handle = new DeviceHandle();
JOptionPane.showMessageDialog(null, "endpoint="+endpoint);
int result = LibUsb.open(device, handle);
if (result != LibUsb.SUCCESS) {
throw new LibUsbException("Unable to open USB device", result);
}
try {
// Use device handle here
claimDevice(handle, 0);
} finally {
LibUsb.close(handle);
}
}
public static void claimDevice(DeviceHandle handle, int interfaceNumber) {
int result = LibUsb.claimInterface(handle, interfaceNumber);
if (result != LibUsb.SUCCESS) {
throw new LibUsbException("Unable to claim interface", result);
}
try {
System.out.println("Device Claimed");
//sendData(handle);
// read(handle,1000);
JOptionPane.showMessageDialog(null, "interface="+interfaceNumber);
read(handle, 2048);
} finally {
result = LibUsb.releaseInterface(handle, interfaceNumber);
if (result != LibUsb.SUCCESS) {
throw new LibUsbException("Unable to release interface", result);
}
}
}
@SuppressWarnings("unused")
public static void sendData(DeviceHandle handle) {
char[] initEP = new char[]{0x1b, '@'};
char[] cutPaper = new char[]{0x1d, 'V', 1};
String initStr = new String(initEP);
String cutStr = new String(cutPaper);
String text = "blabla \n\n\n";
ByteBuffer buffer = ByteBuffer.allocateDirect(8);
buffer.put(new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 });
// SEND INIT BYTE
int transfered = LibUsb.controlTransfer(handle,
(byte) (LibUsb.REQUEST_TYPE_CLASS | LibUsb.RECIPIENT_INTERFACE),
(byte) 0x01, (short) 2, (short) 1, buffer, 5000);
if (transfered < 0) {
throw new LibUsbException("Control transfer failed", transfered);
}
// SENDT TEXT
buffer = ByteBuffer.wrap(text.getBytes());
transfered = LibUsb.controlTransfer(handle,
(byte) (LibUsb.REQUEST_TYPE_CLASS | LibUsb.RECIPIENT_INTERFACE),
(byte) 0x01, (short) 2, (short) 1, buffer, 5000);
if (transfered < 0) {
throw new LibUsbException("Control transfer failed", transfered);
}
/* // SENDT CUT BYTE
buffer = ByteBuffer.wrap(text.getBytes());
transfered = LibUsb.controlTransfer(handle,
(byte) (LibUsb.REQUEST_TYPE_CLASS | LibUsb.RECIPIENT_INTERFACE),
(byte) 0x09, (short) 2, (short) 1, buffer, 5000);
if (transfered < 0) {
throw new LibUsbException("Control transfer failed", transfered);
} */
System.out.println(transfered + " bytes sent");
}
public static ByteBuffer read(DeviceHandle handle, int size)
{
ByteBuffer buffer = BufferUtils.allocateByteBuffer(size).order(ByteOrder.LITTLE_ENDIAN);
IntBuffer transferred = BufferUtils.allocateIntBuffer();
// IntBuffer transferred = BufferUtils.allocateIntBuffer();
long TIMEOUT = 5000;
JOptionPane.showMessageDialog(null, "endpoint_in="+ LibUsb.ENDPOINT_IN);
JOptionPane.showMessageDialog(null, "endpoint_out="+ LibUsb.ENDPOINT_OUT);
JOptionPane.showMessageDialog(null, "handle="+handle);
int result = LibUsb.bulkTransfer(handle, (byte)-128, buffer,
transferred, TIMEOUT);
JOptionPane.showMessageDialog(null, result);
if (result != LibUsb.SUCCESS)
{
throw new LibUsbException("Unable to read data", result);
}
else{System.out.println(transferred.get() + " bytes read from device");
}
return buffer;
}
}
该设备是一个usb鼠标是什么问题？
In order to write i use this code (the write function that I call in my main function):
public static ByteBuffer write(DeviceHandle handle, int size) { ByteBuffer buffer = ByteBuffer.allocateDirect(8); buffer.put(新字节[] {'p'});
String text="p";
//ByteBuffer buffer = ByteBuffer.wrap(text.getBytes());
IntBuffer transferred = BufferUtils.allocateIntBuffer();
long TIMEOUT = 5000;
int result = LibUsb.bulkTransfer(handle, (byte) 0x01, buffer,
transferred, TIMEOUT);
if (result != LibUsb.SUCCESS)
{
throw new LibUsbException("Unable to write data", result);
}
else{System.out.println(transferred.get() + " bytes written to the device");
}
return buffer;
}
但我收到 USB 错误 5：无法写入数据：找不到实体
Why the entity is not found since I use endpoint 0x01...