在Java中通过套接字发送无符号字节

Question

I am attempting to send the following Byte Array to a device running C.

BYTES TO SEND:
80 3f 10 01 00 3c b2 5f 0d

BYTES RECEIVED BY MACHNINE:
00 3f 10 01 00 3c 32 5f 0d

It seems for some reason that java is turning the signed bit into a 0 which is manipulating what the C Machine is reading.

80 -> 00
b2 -> 32

Here is an example of my code:

try
{
    String response;
    Socket clientSocket = new Socket(iPAddress, port);
    DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
    BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

    byte[] bytes = new byte[] { (byte)0x80, 0x3f, 0x10, 0x01, 0x00, 0x3c, (byte) 0xb2, 0x5f, 0x0d};
    outToServer.write(bytes);

    response = inFromServer.readLine();   
    System.out.println("FROM SCU: " + response);
    clientSocket.close();
}
catch(Exception e)
{
    e.printStackTrace();
}

I am absolutely lost as to what I can do now as it seems nothing will work. I do not have access to the C Machine in order to change code.

Answer 1

For me it looks like your "C Machine" use only 7 bits.

0x80 binrary represented is 1000 0000 , and 0xB2 binary is 1011 0010 . If you get 7 bits from right it is 000 0000 = 0x00 and 011 0010 = 0x32

I hope this may help you