Java RandomAccessFile Copy copyFile(File from, File to)

Description

Copy a file from one place to another.

License

Apache License

Parameter

Parameter	Description
from	source file
to	destination file

Exception

Parameter	Description
IOException	an exception

Declaration

public static void copyFile(File from, File to) throws IOException 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright 2010 Dieselpoint, Inc./*from ww w  . ja v  a  2 s.c om*/
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

import java.io.File;

import java.io.IOException;

import java.io.RandomAccessFile;

public class Main {
    /**
     * Copy a file from one place to another.
     * @param from source file
     * @param to destination file
     * @throws IOException
     */
    public static void copyFile(File from, File to) throws IOException {
        RandomAccessFile randFrom = new RandomAccessFile(from, "r");
        RandomAccessFile randTo = new RandomAccessFile(to, "rw");
        appendFile(randTo, randFrom);

        randFrom.close();
        randTo.close();

        to.setLastModified(from.lastModified());
    }

    /**
     * Copy a file from one place to another.
     * @param from source file
     * @param to destination file
     * @throws IOException
     */
    public static void copyFile(String from, String to) throws IOException {
        copyFile(new File(from), new File(to));
    }

    /**
     * Append the contents of extra file to main.
     */
    public static void appendFile(RandomAccessFile main, RandomAccessFile extra) throws IOException {

        // this method uses NIO direct transfer. It delegates the task
        // to the operating system. Only works under 1.4+
        // Unfortunately, can't use this because it crashes with an out of memory error on big files
        //extra.getChannel().transferTo(0, Long.MAX_VALUE, mainFile.getChannel());

        byte[] buf = new byte[1024 * 1024]; // 1 mb
        main.seek(main.length());
        extra.seek(0);

        while (true) {
            int count = extra.read(buf);
            if (count == -1)
                break;
            main.write(buf, 0, count);
        }
    }
}

Related

1. copyFile(File srcFile, File destFile)
2. copyFile(String src, String dst)
3. copyFile(String src, String dst)