Java IO與NIO的一些文件拷貝測試

時間 2019-11-25

標籤 java nio 一些文件拷貝測試欄目 Java 简体版

原文原文鏈接

測試代碼：java

package canghailan;

import java.io.*;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

/**
 * User: canghailan
 * Date: 11-12-9
 * Time: 下午12:38
 */
public class TestIO {
    public static void main(String[] args) throws IOException {
        File[] files = {
                new File("/home/canghailan/java-io-test/1"),
                new File("/home/canghailan/java-io-test/2"),
                new File("/home/canghailan/java-io-test/3")
        };

        int[] bufferSizes = {
                4 * 1024, 8 * 1024, 64 * 1024, 128 * 1024, 256 * 1024, 1024 * 1024
        };

        int times = 5;
        for (File file : files) {
            System.out.println("start test " + file.getName());
            long length = file.length();

            for (int bufferSize : bufferSizes) {
                File byBufferedStream =
                        new File(file.getParentFile(), file.getName() + "-BufferedStream-" + bufferSize);
                File byChannelTransfer =
                        new File(file.getParentFile(), file.getName() + "-ChannelTransfer-" + bufferSize);
                File byBufferedChannel =
                        new File(file.getParentFile(), file.getName() + "-BufferedChannel-" + bufferSize);

                for (int i = 0; i < times; ++i) {
                    long start, end, time;

                    start = System.currentTimeMillis();
                    copyByBufferedStream(file, byBufferedStream, bufferSize);
                    end = System.currentTimeMillis();
                    time = end - start;
                    System.out.println("copyByBufferedStream [" + BtoKB(bufferSize) + "]:" +
                            " copy " + length + "Bytes in " + time + "ms" +
                            " @" + getSpeed(length, time) + "KB/s");


                    start = System.currentTimeMillis();
                    copyByChannelTransfer(file, byChannelTransfer);
                    end = System.currentTimeMillis();
                    time = end - start;
                    System.out.println("copyByChannelTransfer[" + BtoKB(bufferSize) + "]:" +
                            " copy " + length + "Bytes in " + time + "ms" +
                            " @" + getSpeed(length, time) + "KB/s");


                    start = System.currentTimeMillis();
                    copyByBufferedChannel(file, byBufferedChannel, bufferSize);
                    end = System.currentTimeMillis();
                    time = end - start;
                    System.out.println("copyByBufferedChannel[" + BtoKB(bufferSize) + "]:" +
                            " copy " + length + "Bytes in " + time + "ms" +
                            " @" + getSpeed(length, time) + "KB/s");

                    System.out.println();
                }
                System.out.println();
            }
            System.out.println();
        }

    }

    private static void copyByBufferedStream(File src, File dst, int bufferSize) throws IOException {
        InputStream in = new FileInputStream(src);
        OutputStream out = new FileOutputStream(dst);

        byte[] buffer = new byte[bufferSize];
        for (; ; ) {
            int count = in.read(buffer);
            if (count == -1) {
                break;
            }
            out.write(buffer, 0, count);
        }

        in.close();
        out.flush();
        out.close();
    }

    private static void copyByChannelTransfer(File src, File dst) throws IOException {
        FileChannel in = new FileInputStream(src).getChannel();
        FileChannel out = new FileOutputStream(dst).getChannel();

        out.transferFrom(in, 0, in.size());

        in.close();
        out.close();
    }

    private static void copyByBufferedChannel(File src, File dst, int bufferSize) throws IOException {
        FileChannel in = new FileInputStream(src).getChannel();
        FileChannel out = new FileOutputStream(dst).getChannel();

        ByteBuffer buffer = ByteBuffer.allocate(bufferSize);
        for (; ; ) {
            int count = in.read(buffer);
            if (count == -1) {
                break;
            }
            buffer.flip();
            out.write(buffer);
            buffer.clear();
        }

        in.close();
        out.close();
    }

    private static float BtoKB(long bytes) {
        return (float) bytes / 1024;
    }

    private static float MStoS(long ms) {
        return (float) ms / 1000;
    }

    private static float getSpeed(long bytesInTime, long time) {
        return BtoKB(bytesInTime) / MStoS(time);
    }
}

測試環境：

canghailan@canghailan-N81Vf:~$ cat /proc/version
Linux version 3.0.0-13-generic (buildd@rothera) (gcc version 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3) ) #22-Ubuntu SMP Wed Nov 2 13:25:36 UTC 2011
canghailan@canghailan-N81Vf:~$ java -version
java version "1.7.0_01"
Java(TM) SE Runtime Environment (build 1.7.0_01-b08)
Java HotSpot(TM) Server VM (build 21.1-b02, mixed mode)

結論：shell

1.用Java進行文件拷貝時，Stream與Channel性能上幾乎沒有差異。ubuntu

2.Stream的Buffer不是越大越好，如上面數據顯示4K，8K，64K，128K，256K時相差很少，1M時性能反有所降低。性能

測試方法有錯誤之處，敬請指正。測試

[注]三個文件爲隨機選取的40K左右的圖像文件，15M左右的PDF文件，130M左右的壓縮包文件。ui

[附]測試結果：code

start test 1ip

copyByBufferedStream [4.0]: copy 41836Bytes in 0ms @InfinityKB/sget

copyByChannelTransfer[4.0]: copy 41836Bytes in 6ms @6809.2446KB/sit

copyByBufferedChannel[4.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[4.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[4.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[4.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedChannel[4.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [8.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByChannelTransfer[8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [8.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByChannelTransfer[8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [8.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByChannelTransfer[8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[8.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[8.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[8.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedChannel[8.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [64.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByChannelTransfer[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [64.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByChannelTransfer[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [64.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByChannelTransfer[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[64.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[64.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[64.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [128.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[128.0]: copy 41836Bytes in 5ms @8171.0938KB/s

copyByBufferedChannel[128.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [128.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[128.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[128.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [128.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[128.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedChannel[128.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedStream [128.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByChannelTransfer[128.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByBufferedChannel[128.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [128.0]: copy 41836Bytes in 0ms @InfinityKB/s

copyByChannelTransfer[128.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedChannel[128.0]: copy 41836Bytes in 1ms @40855.47KB/s

copyByBufferedStream [256.0]: copy 41836Bytes in 0ms @InfinityKB/s