Read a chunk of data from the file. Java

GetChunkFromFile.java

public byte[] getNextFileChunk() throws IOException {
  FileInputStream fileReader = new FileInputStream(file);

  byte[] b;
  int realLength = CHUNK_SIZE;

  // assuming chunk index starts from 1
  if (currentChunk - 1 == chunksLength) {
      b = new byte[lastChunkSize];
      realLength = lastChunkSize;
  } else {
      b = new byte[CHUNK_SIZE];
  }


  fileReader.read(b, (currentChunk - 1) * CHUNK_SIZE, realLength);

  return b;
}

public int countChunksLength() {
  int fileSize = 0;

  if (file.exists()) {
      fileSize = Integer.parseInt(String.valueOf(file.length()));
  }

  this.chunksLength = fileSize / CHUNK_SIZE;
  this.lastChunkSize = fileSize % CHUNK_SIZE;
  if (lastChunkSize > 0) {
      this.chunksLength++;
  }

  return this.chunksLength;
}