Java FileChannel Copy copy(final File fromFile, final File toFile)

Description

Copy a File.

License

Open Source License

Parameter

Parameter	Description
fromFile	The existing File
toFile	The new File

Return

true if and only if the renaming succeeded; false otherwise

Declaration

public static boolean copy(final File fromFile, final File toFile) 

Method Source Code

//package com.java2s;
/*/*from w  w w  . j  a v a2s .co  m*/
 * Copyright (c) 2017 Eric A. Snell
 *
 * This file is part of eAlvaTag.
 *
 * eAlvaTag is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 *
 * eAlvaTag is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with eAlvaTag.  If not,
 * see <http://www.gnu.org/licenses/>.
 */

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import java.nio.channels.FileChannel;

public class Main {
    /**
     * Copy a File.
     * <p>
     * ToDo refactor AbstractTestCase to use this method as it contains an exact duplicate.
     *
     * @param fromFile The existing File
     * @param toFile   The new File
     *
     * @return <code>true</code> if and only if the renaming succeeded; <code>false</code> otherwise
     */
    public static boolean copy(final File fromFile, final File toFile) {
        try {
            copyThrowsOnException(fromFile, toFile);
            return true;
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * Copy src file to dst file. FileChannels are used to maximize performance.
     *
     * @param source      source File
     * @param destination destination File which will be created or truncated, before copying, if it already exists
     *
     * @throws IOException if any error occurS
     */
    static void copyThrowsOnException(final File source, final File destination) throws IOException {
        // Must be done in a loop as there's no guarantee that a request smaller than request count will complete in one invocation.
        // Setting the transfer size more than about 1MB is pretty pointless because there is no asymptotic benefit. What you're trying
        // to achieve with larger transfer sizes is fewer context switches, and every time you double the transfer size you halve the
        // context switch cost. Pretty soon it vanishes into the noise.
        try (FileInputStream inStream = new FileInputStream(source);
                FileOutputStream outStream = new FileOutputStream(destination)) {
            final FileChannel inChannel = inStream.getChannel();
            final FileChannel outChannel = outStream.getChannel();
            final long size = inChannel.size();
            long position = 0;
            while (position < size) {
                position += inChannel.transferTo(position, 1024L * 1024L, outChannel);
            }
        } //Closeables closed exiting try block in all circumstances
    }
}

Related

1. copy(FileInputStream in, FileOutputStream out)
2. copy(FileInputStream inputStream, FileOutputStream outputStream)
3. copy(FileInputStream iStream, FileOutputStream oStream)
4. copy(final File aCopyFrom, final File aCopyTo)
5. copy(final File source, final File dest)
6. copy(final File src, File dst, final boolean overwrite)
7. copy(final String aSrcPath, final String aDestPath)
8. copy(final String aSrcPath, final String aDestPath)