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我正嘗試使用usb4java（低級別API）與設置爲Windows（x86和x86_64）上的HID設備的USB連接的科學儀器進行通信。有一個非常古老的C++應用程序可以正常工作，但我試圖用各種原因將其替換爲純Java。usb4java：無法讓數據傳輸正常工作
我可以獲取設備描述符並確定接口/端點，但從不會發生異步傳輸（由Device Monitoring Studio檢查），並且從不調用回調。 usb4java不會拋出任何異常，也不知道我是否可以在libusb級別訪問任何日誌（如果甚至可能的話）。我在處理硬件方面是一個完全新手，所以它可能是我錯過的基本東西。
只有一個端點，我不確定C++代碼如何管理雙向通信。代碼中沒有明確提及傳輸類型，因爲所有細節都被隱藏在第三方庫中。
我安裝了libusbK驅動程序，我嘗試了高級實現（javax-usb）。轉移仍然無法完成。
以下是端點描述符轉儲的輸出以及代碼的縮寫版本。
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 8
bInterval 100
extralen 0
extra:
下面的代碼：
import java.nio.*;
import java.util.*;
import org.usb4java.*;
/**
* This class is intended to test USB communication using usb4java
*
*/
public class Test {
private static final String vendorId = "VVV";
private static final String productId = "PPP";
private Context context;
private Device device;
private Handle handle;
static volatile boolean exit = false;
Object synchObj = new Object();
boolean readCompleted = false;
private static final int BUFFER_SIZE = 8;
private final byte[] idQuery = new byte[]{ 0x1d, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
public Test(){
initialize();
if (device == null){
System.out.println("No target devices found");
System.exit(0);
}
boolean loop = true;
//claim interface 0
int result = LibUsb.claimInterface(handle, 0);
if (result != LibUsb.SUCCESS) throw new LibUsbException("Unable to claim interface", result);
//this code doesn't get executed because the transfer never completes correctly
final TransferCallback readCallback = new TransferCallback(){
public void processTransfer(Transfer transfer){
System.out.println(transfer.actualLength() + " bytes sent");
//read the response here
synchronized (synchObj){
readCompleted = true;
synchObj.notify();
}
}
};
//initial request writing the device identification query
write(handle, idQuery, readCallback);
//waiting for the write/response to complete
while (loop){
synchronized (synchObj){
while (!readCompleted){
try{
synchObj.wait();
}
catch (InterruptedException ex){
ex.printStackTrace();
}
}
}
readCompleted = false;
loop = false;
System.out.println("Completed reading");
}
result = LibUsb.releaseInterface(handle, 0);
LibUsb.close(handle);
}
private void initialize(){
try{
context = new Context();
int result = LibUsb.init(context);
if (result != LibUsb.SUCCESS) throw new LibUsbException("Unable to initialize libusb.", result);
DeviceList deviceList = new DeviceList();
result = LibUsb.getDeviceList(context, deviceList);
if (result < 0) throw new LibUsbException("Unable to get device list.", result);
for (int i = 0; i < deviceList.getSize(); i++){
Device dev = deviceList.get(i);
DeviceHandle h = new DeviceHandle();
int res = LibUsb.open(dev, h);
if (res != LibUsb.SUCCESS) continue;
DeviceDescriptor descriptor = new DeviceDescriptor();
result = LibUsb.getDeviceDescriptor(dev, descriptor);
if (result != LibUsb.SUCCESS) throw new LibUsbException("Unable to read device descriptor", result);
String dump = descriptor.dump(h);
if (dump.indexOf("PPP") > -1){
device = dev;
handle = h;
System.out.println("Found target device");
break;
}
}
}
catch (Exception ex){
ex.printStackTrace();
}
}
public static void write(DeviceHandle handle, byte[] data, TransferCallback callback){
ByteBuffer buffer = BufferUtils.allocateByteBuffer(data.length);
buffer.put(data);
Transfer transfer = LibUsb.allocTransfer();
LibUsb.fillInterruptTransfer(transfer, handle, (byte)0x81, buffer, callback, null, 1000);
System.out.println("Sending " + data.length + " bytes to device");
int result = LibUsb.submitTransfer(transfer);
if (result != LibUsb.SUCCESS) throw new LibUsbException("Unable to submit transfer", result);
}
public static void main(String[] args){
Test app = new Test();
}
}
在此先感謝您的任何建議。