what is filekey attribute and how can set filekey attribute of any document in java

Question

plz any buddy share demo program about file version control of any document and how can uniquely identify that document at the time of when we uploading.

http://java2s.com/Tutorials/Java/java.nio.file.attribute/BasicFileAttributes/Java_BasicFileAttributes_fileKey_.htm#Example

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.BasicFileAttributes;
public class Main
{
  public static void main(String[] args) throws Exception  
  {
    BasicFileAttributes attr = null;
    Path path = Paths.get("C:/tutorial/Java/JavaFX", "Topic.txt");
    attr = Files.readAttributes(path, BasicFileAttributes.class);
    System.out.println(attr.fileKey());
  }
}

Answer 1

You seem to be mixing some concepts here: you are talking file version control but filesystem attributes.

A FileAttribute is what its name says: an attribute for a file. What attributes are defined depend on the FileSystem implementation. Paths.get() will return a Path from the default FileSystem.

For instance, files on a Unix system will have attributes to tell whether the file can be read/written/executed by user/group/other. Files on a DOS filesystem will have attributes such as hidden.

But those are dependent on the filesystem. If you copy a file from one system to another, you will lose these attributes.

One can imagine however to write a FileSystem implementation for CVS for instance, where each file has a version; then you could define a CVSFileAttribute with a version, yes.