io - java file operation, how to insert content (not replace content) to a specified location?

Question

Java file operation, how to insert content into the specified location (not replace content)?

Answer 1

There is no real insertion of files because the file size is determined. So the source file can only be replaced with a temporary file.

public void insert(String filename, long offset, byte[] content) {
  RandomAccessFile r = new RandomAccessFile(new File(filename), "rw");
  RandomAccessFile rtemp = new RandomAccessFile(new File(filename + "~"), "rw");
  long fileSize = r.length();
  FileChannel sourceChannel = r.getChannel();
  FileChannel targetChannel = rtemp.getChannel();
  sourceChannel.transferTo(offset, (fileSize - offset), targetChannel);
  sourceChannel.truncate(offset);
  r.seek(offset);
  r.write(content);
  long newOffset = r.getFilePointer();
  targetChannel.position(0L);
  sourceChannel.transferFrom(targetChannel, newOffset, (fileSize - offset));
  sourceChannel.close();
  targetChannel.close();
}

https://stackoverflow.com/que...

Answer 2

Please refer to this:

https://faceghost.com/questio...