一、使用FileStreams复制

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private static void copyFileUsingFileStreams(File source, File dest)
    throws IOException {
    InputStream input = null;
    OutputStream output = null;
    try {
        input = new FileInputStream(source);
        output = new FileOutputStream(dest);
        byte[] buf = new byte[1024];
        int bytesRead;
        while ((bytesRead = input.read(buf)) ！= -1) {
            output.write(buf, 0, bytesRead);
        }
    } finally {
        input.close();
        output.close();
    }
}

二、使用FileChannel复制

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private static void copyFileUsingFileChannels(File source, File dest) throws IOException {
    FileChannel inputChannel = null;
    FileChannel outputChannel = null;
    try {
        inputChannel = new FileInputStream(source).getChannel();
        outputChannel = new FileOutputStream(dest).getChannel();
        outputChannel.transferFrom(inputChannel, 0, inputChannel.size());
    } finally {
        inputChannel.close();
        outputChannel.close();
    }
}

三、使用Commons IO复制

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private static void copyFileUsingApacheCommonsIO(File source, File dest)
    throws IOException {
    FileUtils.copyFile(source, dest);
}

源码：

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private static void doCopyFile(final File srcFile, final File destFile, final boolean preserveFileDate)
    throws IOException {
    if (destFile.exists() && destFile.isDirectory()) {
        throw new IOException("Destination '" + destFile + "' exists but is a directory");
    }

    try (FileInputStream fis = new FileInputStream(srcFile);
         FileChannel input = fis.getChannel();
         FileOutputStream fos = new FileOutputStream(destFile);
         FileChannel output = fos.getChannel()) {
        final long size = input.size(); // TODO See IO-386
        long pos = 0;
        long count = 0;
        while (pos < size) {
            final long remain = size - pos;
            count = remain > FILE_COPY_BUFFER_SIZE ? FILE_COPY_BUFFER_SIZE : remain;
            final long bytesCopied = output.transferFrom(input, pos, count);
            if (bytesCopied == 0) { // IO-385 - can happen if file is truncated after caching the size
                break; // ensure we don't loop forever
            }
            pos += bytesCopied;
        }
    }

    final long srcLen = srcFile.length(); // TODO See IO-386
    final long dstLen = destFile.length(); // TODO See IO-386
    if (srcLen != dstLen) {
        throw new IOException("Failed to copy full contents from '" +
                              srcFile + "' to '" + destFile + "' Expected length: " + srcLen + " Actual: " + dstLen);
    }
    if (preserveFileDate) {
        destFile.setLastModified(srcFile.lastModified());
    }
}

四、使用Java7的Files类复制

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private static void copyFileUsingJava7Files(File source, File dest)
    throws IOException {
    Files.copy(source.toPath(), dest.toPath());
}

五、测试

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package snippet;

import org.apache.commons.io.FileUtils;

import java.io.*;
import java.nio.channels.FileChannel;
import java.nio.file.Files;

public class CopyFilesExample {

    public static void main(String[] args) throws InterruptedException,
            IOException {

        File source = new File("F:\\INSTALL_HISTORY\\ideaIU-2019.1.1.exe");
        File dest = new File("F:\\TEST\\ideaIU-2019.1.1_1.exe");

        // copy file using FileStreams
        long start = System.nanoTime();
        long end;
        copyFileUsingFileStreams(source, dest);
        System.out.printf("%-50s = %20d\n", "Time taken by FileStreams Copy", (System.nanoTime() - start));

        // copy files using java.nio.FileChannelsource = new File("C:\\Users\\nikos7\\Desktop\\files\\sourcefile2.txt");
        dest = new File("F:\\TEST\\ideaIU-2019.1.1_2.exe");
        start = System.nanoTime();
        copyFileUsingFileChannels(source, dest);
        end = System.nanoTime();
        System.out.printf("%-50s = %20d\n", "Time taken by FileChannels Copy", (System.nanoTime() - start));

        // copy file using Java 7 Files classsource = new File("C:\\Users\\nikos7\\Desktop\\files\\sourcefile3.txt");
        dest = new File("F:\\TEST\\ideaIU-2019.1.1_3.exe");
        start = System.nanoTime();
        copyFileUsingJava7Files(source, dest);
        end = System.nanoTime();
        System.out.printf("%-50s = %20d\n", "Time taken by Java7 Files Copy", (System.nanoTime() - start));

        // copy files using apache commons iosource = new File("C:\\Users\\nikos7\\Desktop\\files\\sourcefile4.txt");
        dest = new File("F:\\TEST\\ideaIU-2019.1.1_4.exe");
        start = System.nanoTime();
        copyFileUsingApacheCommonsIO(source, dest);
        end = System.nanoTime();
        System.out.printf("%-50s = %20d\n", "Time taken by Apache Commons IO Copy", (System.nanoTime() - start));

    }

    private static void copyFileUsingFileStreams(File source, File dest)
            throws IOException {
        InputStream input = null;
        OutputStream output = null;
        try {
            input = new FileInputStream(source);
            output = new FileOutputStream(dest);
            byte[] buf = new byte[1024];
            int bytesRead;
            while ((bytesRead = input.read(buf)) > 0) {
                output.write(buf, 0, bytesRead);
            }
        } finally {
            input.close();
            output.close();
        }
    }

    private static void copyFileUsingFileChannels(File source, File dest)
            throws IOException {
        FileChannel inputChannel = null;
        FileChannel outputChannel = null;
        try {
            inputChannel = new FileInputStream(source).getChannel();
            outputChannel = new FileOutputStream(dest).getChannel();
            outputChannel.transferFrom(inputChannel, 0, inputChannel.size());
        } finally {
            inputChannel.close();
            outputChannel.close();
        }
    }

    private static void copyFileUsingJava7Files(File source, File dest)
            throws IOException {
        Files.copy(source.toPath(), dest.toPath());
    }

    private static void copyFileUsingApacheCommonsIO(File source, File dest)
            throws IOException {
        FileUtils.copyFile(source, dest);
    }

}

结果：

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Time taken by FileStreams Copy                     =           3307186847
Time taken by FileChannels Copy                    =            355407223
Time taken by Java7 Files Copy                     =            434544647
Time taken by Apache Commons IO Copy               =           2018366048