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Java IO与NIO的一些文件拷贝测试

2011-12-09 13:40 3019 查看

测试代码：

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);
}
}

测试环境：

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)

结论：

1.用Java进行文件拷贝时，Stream与Channel性能上几乎没有差别。

2.Stream的Buffer不是越大越好，如上面数据显示4K，8K，64K，128K，256K时相差不多，1M时性能反有所下降。

测试方法有错误之处，敬请指正。

[注]三个文件为随机选取的40K左右的图像文件，15M左右的PDF文件，130M左右的压缩包文件。

[附]测试结果：

start test 1

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

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