Java Usb communication Usb4Java ( Printer USB)

[DHARA MISTRY]

Hello

I’m recently developing an application that has to communicate with a POS thermal printer using low level API usb4java and using zadig tool

Here is the workflow in this post
1. get the device list
2. choose device (id and vendor)
3. claim the device
4. send data

I am getting error : "data must be direct buffer "

Code : 

import java.nio.ByteBuffer;

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 DetectUSB {

 

    public static void main(String[] args) {

 

        // Create the libusb context

        Context context = new Context();

        findDevice(context, (short) (0x1203), (short) (0x0128));

        // 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) {

 

        DeviceHandle handle = new DeviceHandle();

 

        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);

            

        } 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.wrap(initStr.getBytes());

        // 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");

    }

}

Error :

Bus 002, Device 001: Vendor 8086, Product 8c2d

Bus 001, Device 001: Vendor 8086, Product 8c26

Bus 002, Device 004: Vendor 0bda, Product 0129

Bus 002, Device 003: Vendor 1203, Product 0128

Device Found

Device Claimed

Exception in thread "main" java.lang.IllegalArgumentException: data must be a direct buffer

at org.usb4java.LibUsb.controlTransfer(Native Method)

at detectUSB.DetectUSB.sendData(DetectUSB.java:124)

at detectUSB.DetectUSB.claimDevice(DetectUSB.java:102)

at detectUSB.DetectUSB.getDeviceHandle(DetectUSB.java:87)

at detectUSB.DetectUSB.findDevice(DetectUSB.java:64)

at detectUSB.DetectUSB.main(DetectUSB.java:19)

Please any one help with this ?

[Dennis Sheirer]

Instead of using a jvm managed byte buffer:

ByteBuffer buffer = ByteBuffer.wrap(initStr.getBytes());

You need to create a direct (native) byte buffer that gets allocated outside of the jvm managed memory space and is accessible by the low level libusb library.  Create the direct buffer and then overlay your initStr bytes and then make your call.

Read about it here:
http://docs.oracle.com/javase/7/docs/api/java/nio/ByteBuffer.html

[Stel Al]

I have the same problem can you please help us???