Java FileChannel Copy copy(final File src, File dst, final boolean overwrite)

Description

Copy source file to destination.

License

Open Source License

Parameter

Parameter	Description
src	source file
dst	destination file or path
overwrite	overwrite destination file

Declaration

@SuppressWarnings("unused")
private static void copy(final File src, File dst, final boolean overwrite) throws IOException 

Method Source Code

//package com.java2s;
/*//from   ww  w .j  ava  2  s.co m
 * Copyright (c) 2007-2013, 2015 Eike Stepper (Berlin, Germany) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Eike Stepper - initial API and implementation
 */

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 source file to destination. If destination is a path then source file name is appended. If destination file
     * exists then: overwrite=true - destination file is replaced; overwite=false - exception is thrown.
     *
     * @param src
     *          source file
     * @param dst
     *          destination file or path
     * @param overwrite
     *          overwrite destination file
     * @exception IOException
     *              I/O problem
     */
    @SuppressWarnings("unused")
    private static void copy(final File src, File dst, final boolean overwrite) throws IOException {
        if (!src.isFile() || !src.exists()) {
            throw new IllegalArgumentException("Source file '" + src.getAbsolutePath() + "' not found!"); //$NON-NLS-1$ //$NON-NLS-2$
        }

        if (dst.exists()) {
            if (dst.isDirectory()) {
                // name
                dst = new File(dst, src.getName());
            } else if (dst.isFile()) {
                if (!overwrite) {
                    throw new IllegalArgumentException(
                            "Destination file '" + dst.getAbsolutePath() + "' already exists!"); //$NON-NLS-1$ //$NON-NLS-2$
                }
            } else {
                throw new IllegalArgumentException("Invalid destination object '" + dst.getAbsolutePath() + "'!"); //$NON-NLS-1$ //$NON-NLS-2$
            }
        }

        File dstParent = dst.getParentFile();
        if (!dstParent.exists()) {
            if (!dstParent.mkdirs()) {
                throw new IOException("Failed to create directory " + dstParent.getAbsolutePath()); //$NON-NLS-1$
            }
        }

        long fileSize = src.length();
        if (fileSize > 20971520l) { // for larger files (20Mb) use streams
            FileInputStream in = new FileInputStream(src);
            FileOutputStream out = new FileOutputStream(dst);
            try {
                int doneCnt = -1, bufSize = 32768;
                byte buf[] = new byte[bufSize];
                while ((doneCnt = in.read(buf, 0, bufSize)) >= 0) {
                    if (doneCnt == 0) {
                        Thread.yield();
                    } else {
                        out.write(buf, 0, doneCnt);
                    }
                }

                out.flush();
            } finally {
                try {
                    in.close();
                } catch (IOException e) {
                }

                try {
                    out.close();
                } catch (IOException e) {
                }
            }
        } else { // smaller files, use channels
            FileInputStream fis = new FileInputStream(src);
            FileOutputStream fos = new FileOutputStream(dst);
            FileChannel in = fis.getChannel(), out = fos.getChannel();

            try {
                long offs = 0, doneCnt = 0, copyCnt = Math.min(65536, fileSize);
                do {
                    doneCnt = in.transferTo(offs, copyCnt, out);
                    offs += doneCnt;
                    fileSize -= doneCnt;
                }

                while (fileSize > 0);
            } finally { // cleanup
                try {
                    in.close();
                } catch (IOException e) {
                }

                try {
                    out.close();
                } catch (IOException e) {
                }

                try {
                    fis.close();
                } catch (IOException e) {
                }

                try {
                    fos.close();
                } catch (IOException ex) {
                }
            }
        }
    }
}

Related

1. copy(FileInputStream inputStream, FileOutputStream outputStream)
2. copy(FileInputStream iStream, FileOutputStream oStream)
3. copy(final File aCopyFrom, final File aCopyTo)
4. copy(final File fromFile, final File toFile)
5. copy(final File source, final File dest)
6. copy(final String aSrcPath, final String aDestPath)
7. copy(final String aSrcPath, final String aDestPath)
8. copy(String fromPath, String toPath)
9. copy(String source, String destination)