Java ByteBuffer to String

Question

Is this a correct approach to convert ByteBuffer to String in this way,

String k = \"abcd\";
ByteBuffer b = ByteBuffer.wrap(k.getBytes());
String v = new Str         


        

Answer 1

Here is a simple function for converting a byte buffer to string:

public String byteBufferToString(ByteBuffer bufferData) {
    byte[] buffer = new byte[bufferData.readableByteCount()];
    // read bufferData and insert into buffer 
    data.read(buffer);
    // CharsetUtil supports UTF_16, ASCII, and many more
    String text = new String(buffer, CharsetUtil.UTF_8);
    System.out.println("Text: "+text);
    return text;
}

Answer 2

The answers referring to simply calling array() are not quite correct: when the buffer has been partially consumed, or is referring to a part of an array (you can ByteBuffer.wrap an array at a given offset, not necessarily from the beginning), we have to account for that in our calculations. This is the general solution that works for buffers in all cases (does not cover encoding):

if (myByteBuffer.hasArray()) {
    return new String(myByteBuffer.array(),
        myByteBuffer.arrayOffset() + myByteBuffer.position(),
        myByteBuffer.remaining());
} else {
    final byte[] b = new byte[myByteBuffer.remaining()];
    myByteBuffer.duplicate().get(b);
    return new String(b);
}

For the concerns related to encoding, see Andy Thomas' answer.

Answer 3

Try this:

new String(bytebuffer.array(), "ASCII");

NB. you can't correctly convert a byte array to a String without knowing its encoding.

I hope this helps

Answer 4

Notice (aside from the encoding issue) that some of the more complicated code linked goes to the trouble of getting the "active" portion of the ByteBuffer in question (for example by using position and limit), rather than simply encoding all of the bytes in the entire backing array (as many of the examples in these answers do).