Schnell große Dateien kopieren mit Java NIO

Thomas Darimont

Thomas Darimont

Erfahrenes Mitglied
Hallo,

schaut mal hier:
Java: 
/**
 * 
 */
package de.tutorials;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.ByteChannel;
import java.nio.channels.FileChannel;
import java.nio.channels.SocketChannel;
import java.nio.channels.WritableByteChannel;

/**
 * @author Tom
 * 
 */
public class FastFileCopyExample {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		copy(file("D:/VMWare/40g xp development/xp-s005.vmdk"),
				file("c:/temp/xp-s005.vmdk"));
	}

	private static File file(String path) {
		return new File(path);
	}
	
	public static void copy(File source, File destination) {
		try {
			FileInputStream fileInputStream = new FileInputStream(source);
			FileOutputStream fileOutputStream = new FileOutputStream(
					destination);

			FileChannel inputChannel = fileInputStream.getChannel();
			FileChannel outputChannel = fileOutputStream.getChannel();

			transfer(inputChannel, outputChannel, source.length(), 1024 * 1024 * 32 /* 32 MB */, true,true);

			fileInputStream.close();
			fileOutputStream.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void transfer(FileChannel fileChannel,
			ByteChannel byteChannel, long lengthInBytes,
			long chunckSizeInBytes, boolean verbose, boolean fromFile)
			throws IOException {

		long overallBytesTransfered = 0L;
		long time = -System.currentTimeMillis();
		while (overallBytesTransfered < lengthInBytes) {

			long bytesTransfered = 0L;

			if (fromFile) {
				bytesTransfered = fileChannel.transferTo(0, Math.min(
						chunckSizeInBytes, lengthInBytes
								- overallBytesTransfered), byteChannel);
			} else {
				bytesTransfered = fileChannel.transferFrom(byteChannel,
						overallBytesTransfered, Math.min(chunckSizeInBytes,
								lengthInBytes - overallBytesTransfered));
			}

			overallBytesTransfered += bytesTransfered;

			if (verbose) {
				System.out.printf(
						"overall bytes transfered: %s progress %s%%\n",
						overallBytesTransfered, Math
								.round(overallBytesTransfered
										/ ((double) lengthInBytes) * 100.0));
			}

		}
		time += System.currentTimeMillis();

		if (verbose) {
			System.out.printf("Transfered: %s bytes in: %s s -> %s kbytes/s",
					overallBytesTransfered, time / 1000,
					(overallBytesTransfered / 1024.0) / (time / 1000.0));
		}

	}
}

Code: 
overall bytes transfered: 33554432 progress 2%
overall bytes transfered: 67108864 progress 3%
overall bytes transfered: 100663296 progress 5%
overall bytes transfered: 134217728 progress 6%
overall bytes transfered: 167772160 progress 8%
overall bytes transfered: 201326592 progress 9%
overall bytes transfered: 234881024 progress 11%
overall bytes transfered: 268435456 progress 13%
overall bytes transfered: 301989888 progress 14%
overall bytes transfered: 335544320 progress 16%
overall bytes transfered: 369098752 progress 17%
overall bytes transfered: 402653184 progress 19%
overall bytes transfered: 436207616 progress 20%
overall bytes transfered: 469762048 progress 22%
overall bytes transfered: 503316480 progress 23%
overall bytes transfered: 536870912 progress 25%
overall bytes transfered: 570425344 progress 27%
overall bytes transfered: 603979776 progress 28%
overall bytes transfered: 637534208 progress 30%
overall bytes transfered: 671088640 progress 31%
overall bytes transfered: 704643072 progress 33%
overall bytes transfered: 738197504 progress 34%
overall bytes transfered: 771751936 progress 36%
overall bytes transfered: 805306368 progress 38%
overall bytes transfered: 838860800 progress 39%
overall bytes transfered: 872415232 progress 41%
overall bytes transfered: 905969664 progress 42%
overall bytes transfered: 939524096 progress 44%
overall bytes transfered: 973078528 progress 45%
overall bytes transfered: 1006632960 progress 47%
overall bytes transfered: 1040187392 progress 49%
overall bytes transfered: 1073741824 progress 50%
overall bytes transfered: 1107296256 progress 52%
overall bytes transfered: 1140850688 progress 53%
overall bytes transfered: 1174405120 progress 55%
overall bytes transfered: 1207959552 progress 56%
overall bytes transfered: 1241513984 progress 58%
overall bytes transfered: 1275068416 progress 59%
overall bytes transfered: 1308622848 progress 61%
overall bytes transfered: 1342177280 progress 63%
overall bytes transfered: 1375731712 progress 64%
overall bytes transfered: 1409286144 progress 66%
overall bytes transfered: 1442840576 progress 67%
overall bytes transfered: 1476395008 progress 69%
overall bytes transfered: 1509949440 progress 70%
overall bytes transfered: 1543503872 progress 72%
overall bytes transfered: 1577058304 progress 74%
overall bytes transfered: 1610612736 progress 75%
overall bytes transfered: 1644167168 progress 77%
overall bytes transfered: 1677721600 progress 78%
overall bytes transfered: 1711276032 progress 80%
overall bytes transfered: 1744830464 progress 81%
overall bytes transfered: 1778384896 progress 83%
overall bytes transfered: 1811939328 progress 85%
overall bytes transfered: 1845493760 progress 86%
overall bytes transfered: 1879048192 progress 88%
overall bytes transfered: 1912602624 progress 89%
overall bytes transfered: 1946157056 progress 91%
overall bytes transfered: 1979711488 progress 92%
overall bytes transfered: 2013265920 progress 94%
overall bytes transfered: 2046820352 progress 96%
overall bytes transfered: 2080374784 progress 97%
overall bytes transfered: 2113929216 progress 99%
overall bytes transfered: 2143158272 progress 100%
Transfered: 2143158272 bytes in: 33 s -> 62548.280087265775 kbytes/s

Für das kopieren von 2 gb brauch ich damit nur 33 s.

Gruß Tom
 
Hallo,

N bisschen viel Code für die Methode FileChannel.transferTo/transferFrom
Zum Vergrößern anklicken....

Was soll denn das heißen? ;-) Wenn man eine Datei häppchenweise via FileChannel transferTo/From transportieren möchte bleibt einem nichts anderes übrig als diesen Code drum herum zu bauen.

Kannst aber auch gerne mal versuchen eine 2gb datei mit fileChannel.transferTo driekt zu versenden :p
Vielleicht bekommst du das auch schneller hin ;-)

Außerdem kann die Transfer Methode nicht nur von einem FileChannel lesen und in einen anderen ByteChannel reinschreiben sondern auch umgekehrt.

Das "pseudo" logging dient nur zur Verdeutlichung...

Was evtl. in diesem Zusammenhang auch noch interessant ist: http://commons.apache.org/io/
Zum Vergrößern anklicken....
CommonsIO ist mir wohl bekannt ;-) Dort wird in der Klasse FileUtils auch der FileChannel verwendet. Leider
kann man damit aber nur Dateien kopieren die auch in den Speicher passen...

Da meine Variante Blockweise kopiert gibts hier keine Größenbeschränkungen.

Gruß Tom
 
Hehe, wollte doch nur ein bisschen stänkern ;) .

Die IO-Tools sollten nicht als Verbesserung von deinem Code verstanden werden, sondern als Ergänzung. Wer sich mit dem performanten Kopieren von Dateien beschäftigt, der sollte eben evtl. auch mal da einen Blick rein werfen.

Schönes Wochenende!
 
Hallo Tom,
ich habe Deine Routinen nch nicht ausprobiert, aber meine Frage ...ab welcher Java-Version funktioniert Dein Beispiel?

mit neugierigem Gruß

Takidoso
 
Mh nur mal eine Frage, hast du die kopierten Dateien auch mal getestet? Weil wenn ich hab das mal mit zips probiert und war von dem speed direkt beeindruckt, aber die zips sind nur solange valid wie sie kleiner als ein chunk sind.
Würde meinen aber dem 2. Chunk schreibt der da Bitmüll beim >Kopieren rein, was auch den speed erklären würde :p
 
Hallo,

in der alten transfer-Methode gabs einen Bug der hier diskutiert wurde:
http://www.tutorials.de/forum/java/245134-datei-mittels-tcp-uebertragen.html

Gefixedte Version:
Java: 
package de.tutorials;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.ByteChannel;
import java.nio.channels.FileChannel;

public class FastFileCopyExample {

  /**
   * @param args
   */
  public static void main(String[] args) {
    copy(file("c:/foo.zip"), file("c:/foo-2.zip"));
  }


  private static File file(String path) {
    return new File(path);
  }


  public static void copy(File source, File destination) {
    try {
      FileInputStream fileInputStream = new FileInputStream(source);
      FileOutputStream fileOutputStream = new FileOutputStream(destination);

      FileChannel inputChannel = fileInputStream.getChannel();
      FileChannel outputChannel = fileOutputStream.getChannel();

      transfer(inputChannel, outputChannel, source.length(), 1024 * 1024 * 32 /* 32 MB */, true);

      fileInputStream.close();
      fileOutputStream.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }


  public static void transfer(FileChannel inputChannel, ByteChannel outputChannel, long lengthInBytes, long chunckSizeInBytes, boolean verbose) throws IOException {
    long overallBytesTransfered = 0L;
    long time = -System.currentTimeMillis();
    while (overallBytesTransfered < lengthInBytes) {
      long bytesToTransfer = Math.min(chunckSizeInBytes, lengthInBytes - overallBytesTransfered);
      long bytesTransfered = inputChannel.transferTo(overallBytesTransfered, bytesToTransfer, outputChannel);

      overallBytesTransfered += bytesTransfered;

      if (verbose) {
        long percentageOfOverallBytesTransfered = Math.round(overallBytesTransfered / ((double) lengthInBytes) * 100.0);
        System.out.printf("overall bytes transfered: %s progress %s%%\n", overallBytesTransfered, percentageOfOverallBytesTransfered);
      }

    }
    time += System.currentTimeMillis();

    if (verbose) {
      double kiloBytesPerSecond = (overallBytesTransfered / 1024.0) / (time / 1000.0);
      System.out.printf("Transfered: %s bytes in: %s s -> %s kbytes/s", overallBytesTransfered, time / 1000, kiloBytesPerSecond);
    }

  }
}

Gruß Tom
 
Ah, ich hät ja auch mal meine Gehirn-Augen-Koordination besser benutzen können.
Danke, ja so läuft die natürlich gut und richtig :D
 
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