How to move or copy a file in Java

Question

Does Java provide any standard library that handles the common file operations like moving/copying files/folders?

Answer 1

You can follow the below java.nio operations:

public static void fileCopy(File srcFile, File destFile) throws IOException {
    if(!destFile.exists()) {
        destFile.createNewFile();
    }

    FileChannel src= null;
    FileChannel dstn= null;
    try {
        src= new FileInputStream(srcFile).getChannel();
        dstn= new FileOutputStream(destFile).getChannel();

        // previous code: destination.transferFrom(source, 0, source.size());
        // to avoid infinite loops, should be:
        long count = 0;
        long size = src.size();              
        while((count += dstn.transferFrom(src, count, size-count))<size);
    }
    finally {
        if(src != null) {
            src.close();
        }
        if(dstn!= null) {
            dstn.close();
        }
    }
}

Hope this helps!!

Answer 2

The new JAVA Specification Request 203 -NIO will have support for these common operations.

There are a few considerations however,

File.renameTo generally works only on the same file system volume. This is most likely equivalent to a "mv" command. You can use it if you wish, but for general copy and move support, you'll need to have a fallback.

When a rename doesn't work you will need to actually copy the file (deleting the original with File.delete if it's a "move" operation). 

To do this with the efficiently, use the FileChannel.transferTo or FileChannel.transferFrom methods. 

The implementation is platform specific, but in general, when copying from one file to another, implementations avoid transporting data back and forth between kernel and user space, yielding a big boost in efficiency.