Resetting byte[] buffer to zeros?

Question

In the following code for sockets, I declare a byte buffer and listen for client messages in a loop:

// Create some buffer
byte[] buffer = new byte[512];

while (true)
{
    // Listen for messages from Client

    int length = socket.getInputStream().read(buffer);

    if (length != -1)
        System.out.println(new String(buffer));
    else
        break;

    // Reset buffer here to zeros?
}

Each time I'd require to reset the contents of buffer to receive a new message. What's the proper way to do this?

That's not a reliable way to receive a string over a socket. There's no guarantee a complete encoded byte array will be returned in a single `read()` call. Use `DataInput/DataOutput` `readUTF()/writeUTF()` or something equally reliable. — President James K. Polk, Jun 09 '17 at 12:59
Yes, that could work, especially if you use the methods of `DataInput/DataOutput` such as `readInt()/writeInt()` and `readFully()`. — President James K. Polk, Jun 10 '17 at 22:06

score 20 · Answer 1 · answered Jun 09 '17 at 12:04

20

Agree with dasblinkenlight answers, but to answer the question itself (how to reset an array), you can use Arrays.fill to set a value to every cell

byte[] array = new byte[10];
Arrays.fill(array, (byte)0);

answered Jun 09 '17 at 12:04

AxelH

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score 8 · Accepted Answer · answered Jun 09 '17 at 10:58

You don't need to reset the buffer, you need to a String constructor that does not go past the end of the part of the buffer that has the bytes received:

if (length != -1) {
    System.out.println(new String(buffer, 0, length));
}

Now your code will work even if the buffer is dirty.

Note: For better portability pass the desired Charset to String constructor. Otherwise the String you construct may not match the string that has been transmitted to you through the socket.

Resetting byte[] buffer to zeros?

2 Answers2