文件传输的几种方式效率比较 博客分类： IO流 ioniochannletransferrenameTo

package com.yonge.nio;

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

/**
 * 文件传输几种方式比较
 * @author wb-gaoy
 * @version $Id: ChannelTest.java,v 0.1 2012-12-13 下午7:28:40 wb-gaoy Exp $
 */
public class ChannelTest {

    public boolean copyFileByIO(File srcFile, File targetDir) throws IOException {
        FileInputStream fis = new FileInputStream(srcFile);
        FileOutputStream fos = new FileOutputStream(targetDir + File.separator + srcFile.getName());
        byte[] bytes = new byte[1024 * 1024];
        int length = -1;
        while ((length = fis.read(bytes)) != -1) {
            fos.write(bytes, 0, length);
        }
        fis.close();
        fos.close();
        return true;
    }

    public boolean copyFileByNIO(File srcFile, File targetDir) throws IOException {
        FileInputStream fis = new FileInputStream(srcFile);
        FileOutputStream fos = new FileOutputStream(targetDir + File.separator + srcFile.getName());
        try {
            FileChannel fisChannel = fis.getChannel();
            FileChannel fosChannel = fos.getChannel();
            ByteBuffer byteBuffer = ByteBuffer.allocate(1024 * 1024);
            while (fisChannel.read(byteBuffer) != -1) {
                byteBuffer.flip();
                fosChannel.write(byteBuffer);
                byteBuffer.clear();
            }
            fosChannel.close();
            fisChannel.close();
        } finally {
            fis.close();
            fos.close();
        }
        return true;
    }

    public boolean copyFileByTransfer(File srcFile, File targetDir) throws IOException {
        FileInputStream fis = new FileInputStream(srcFile);
        FileOutputStream fos = new FileOutputStream(targetDir + File.separator + srcFile.getName());
        try {
            FileChannel fisChannel = fis.getChannel();
            FileChannel fosChannel = fos.getChannel();
            fisChannel.transferTo(0, fisChannel.size(), fosChannel);
            fosChannel.close();
            fisChannel.close();
        } finally {
            fis.close();
            fos.close();
        }
        return true;
    }

    //注意：如果目标文件已经存在或磁盘间的格式不一样（例如源文件磁盘是ntfs，而目标磁盘是fat32），则不会成功
    public boolean moveFile(File srcFile, File targetFile) {
        srcFile.renameTo(new File(targetFile + File.separator + srcFile.getName()));
        return true;
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        final ChannelTest test = new ChannelTest();
        final File targetDir = new File("e:/temp");
        Thread thread1 = new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    long start = System.currentTimeMillis();
                    test.copyFileByIO(new File("e:/ppl20120921145445000611.rar"), targetDir);
                    System.out.println("IO cost:" + (System.currentTimeMillis() - start) + "ms");
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }, "A");
        thread1.start();

        Thread thread2 = new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    long start = System.currentTimeMillis();
                    test.copyFileByNIO(new File("e:/ppl20120921145445000612.rar"), targetDir);
                    System.out.println("NIO cost:" + (System.currentTimeMillis() - start) + "ms");
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }, "B");
        thread2.start();

        Thread thread3 = new Thread(new Runnable() {

            @Override
            public void run() {
                long start = System.currentTimeMillis();
                test.moveFile(new File("e:/ppl20120921145445000613.rar"), targetDir);
                System.out.println("Move cost:" + (System.currentTimeMillis() - start) + "ms");
            }
        }, "C");
        thread3.start();

        Thread thread4 = new Thread(new Runnable() {

            @Override
            public void run() {
                long start = System.currentTimeMillis();
                try {
                    test.copyFileByTransfer(new File("e:/ppl20120921145445000614.rar"), targetDir);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                System.out.println("Transfer cost:" + (System.currentTimeMillis() - start) + "ms");
            }
        }, "D");
        thread4.start();
    }

}

 上面是四种文件传输方式，测试结果是transfer的效率最低，而网上都说这种效率高，不知道是什么原因，欢迎大家测试一下，说说各自的想法。