How can I remove bytes from a ByteArrayOutputStream?
So the first four bytes of my ByteArrayOutputStream contain the length of a header in my stream. I need to remove that header from the stream and go on with my business.
ByteArrayOutputStream oStream = new ByteArrayOutputStream();
/* populate ByteArrayOutputStream */
//grab first int
int headerLength = oStream.toByteArray()[4];
//remove headerLength
String newString = oStream.toString().substring(jsonLength, oStream.size());
oStream.write(newString.getBytes());
I don't think this is the proper way to go about this though, does anyone have any suggestions?
Answer
The simple answer is to write the 4 bytes in the first place ... if you can achieve that.
Another answer would be to write a custom FilterOutputStream subclass that ignores the first 4 bytes written.
Yet another is to extract the bytes, and then use one of the Arrays.copy methods to create a new byte array containing the "slice" of the original that you require; e.g.
byte[] subarray = Arrays.copyOfRange(original, 4, original.length - 4);
Or if your application can cope with an "undefined" area at the end of the byte array, you can do something like this:
System.arraycopy(array, 4, array.length - 4, array, 0); // YMMV - check javadoc
Finally, depending on what you are using the byte array for, there's a good chance you can ignore the first 4 bytes without removing them. For instance, you can do this when writing bytes to a stream, when creating a string from bytes, when copying bytes to a ByteBuffer, and so on.