Java FileChannel Copy copyThrowsOnException(final File source, final File destination)

Description

Copy src file to dst file.

License

Open Source License

Parameter

Parameter	Description
source	source File
destination	destination File which will be created or truncated, before copying, if it already exists

Exception

Parameter	Description
IOException	if any error occurS

Declaration

static void copyThrowsOnException(final File source, final File destination) throws IOException 

Method Source Code

//package com.java2s;
/*/*w w w  .j a  v a 2 s .c  o  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 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. copyLarge(FileInputStream in, FileOutputStream out)
2. copyNio(final File source_file, final File destination_file)
3. copyRec(File src, File dst)
4. copyStream(InputStream in, long length, File out)
5. copyStreamToFile(InputStream inStream, File file)
6. copyTo(File srcFile, File destFile)
7. copyToFolderAs(File fromFile, File folder, String asName)
8. copyToTemp(File srcFile)
9. copyToTempDirectory(final String file)