使用Java NIO可以更快地复制文件。我发现两种主要通过互联网执行此工作的方法。

public static void copyFile(File sourceFile, File destinationFile) throws IOException {
    if (!destinationFile.exists()) {
        destinationFile.createNewFile();
    }

    FileChannel source = null;
    FileChannel destination = null;
    try {
        source = new FileInputStream(sourceFile).getChannel();
        destination = new FileOutputStream(destinationFile).getChannel();
        destination.transferFrom(source, 0, source.size());
    } finally {
        if (source != null) {
            source.close();
        }
        if (destination != null) {
            destination.close();
        }
    }
}

在20个对Java开发人员非常有用的Java代码段中，我找到了不同的注释和技巧：

public static void fileCopy(File in, File out) throws IOException {
    FileChannel inChannel = new FileInputStream(in).getChannel();
    FileChannel outChannel = new FileOutputStream(out).getChannel();
    try {
        // inChannel.transferTo(0, inChannel.size(), outChannel); // original -- apparently has trouble copying large files on Windows
        // magic number for Windows, (64Mb - 32Kb)
        int maxCount = (64 * 1024 * 1024) - (32 * 1024);
        long size = inChannel.size();
        long position = 0;
        while (position < size) {
            position += inChannel.transferTo(position, maxCount, outChannel);
        }
    } finally {
        if (inChannel != null) {
            inChannel.close();
        }
        if (outChannel != null) {
            outChannel.close();
        }
    }
}

但我没有发现或理解什么意思

“ Windows的幻数，（64Mb-32Kb）”

它说inChannel.transferTo(0, inChannel.size(), outChannel)在Windows
中有问题，对于此方法，最佳值为32768（=（64 * 1024 * 1024）-（32 * 1024））字节。