今天review代码也看到了“大神”用老方法来实现文件拷贝。今天归结一下使用Java语言怎样实现高速文件复制：

代码1——使用文件通道的方式：

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.nio.channels.FileChannel;

public class Test {

	public static void main(String[] args){

		long start = System.currentTimeMillis();

		FileInputStream fileInputStream = null;

        FileOutputStream fileOutputStream = null;

        FileChannel inFileChannel = null;

        FileChannel outFileChannel = null;

        try {

        	fileInputStream = new FileInputStream(new File("C:\\from\\不是闹着玩的.flv"));

        	fileOutputStream = new FileOutputStream(new File("C:\\to\\不是闹着玩的.flv"));

            inFileChannel = fileInputStream.getChannel();

            outFileChannel = fileOutputStream.getChannel();

            inFileChannel.transferTo(0, inFileChannel.size(), outFileChannel);//连接两个通道。从in通道读取数据写入out通道。

} catch (IOException e) {

            e.printStackTrace();

        } finally {

            try {

            	if(fileInputStream != null){

            		fileInputStream.close();

            	}

            	if(inFileChannel != null){

	                inFileChannel.close();

            	}

                if(fileOutputStream != null){

	                fileOutputStream.close();

                }

                if(outFileChannel != null){

	                outFileChannel.close();

                }

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

		long end = System.currentTimeMillis();

		System.out.println("视频文件从“from”目录拷贝到“to”文件须要" + (end - start) + "毫秒。

");

	}

}

代码执行结果为：

代码2——使用缓冲输入输出流

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

public class Test {

	public static void main(String[] args){

		long start = System.currentTimeMillis();

		InputStream fileInputStream = null;

        OutputStream fileOutputStream = null;

        try {

        	fileInputStream = new BufferedInputStream( new FileInputStream(new File("C:\\from\\不是闹着玩的.flv")));

        	fileOutputStream = new BufferedOutputStream(new FileOutputStream(new File("C:\\to\\不是闹着玩的.flv")));

        	byte[] bufferArray = new byte[1024*1024];

            int length;

            while ((length = fileInputStream.read(bufferArray)) != -1) {

                fileOutputStream.write(bufferArray, 0, length);

            }

        } catch (IOException e) {

            e.printStackTrace();

        } finally {

            try {

            	if(fileInputStream != null){

            		fileInputStream.close();

            	}

                if(fileOutputStream != null){

	                fileOutputStream.close();

                }

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

		long end = System.currentTimeMillis();

		System.out.println("视频文件从“from”目录拷贝到“to”文件须要" + (end - start) + "毫秒。");

	}

}

代码执行结果为：
  

代码3——使用文件输入输出流的方式：

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

public class Test {

	public static void main(String[] args){

		long start = System.currentTimeMillis();

		FileInputStream fileInputStream = null;

		FileOutputStream fileOutputStream = null;

		try{

			fileInputStream = new FileInputStream(new File("C:\\from\\不是闹着玩的.flv")); //读入原文件

			fileOutputStream = new FileOutputStream("C:\\to\\不是闹着玩的.flv");

	       	byte[] bufferArray = new byte[1024*1024];

	       	int length;

	       	while ((length = fileInputStream.read(bufferArray)) != -1) {

	       		fileOutputStream.write(bufferArray, 0, length);

	       	}

		} catch (IOException e) {

            e.printStackTrace();

        } finally {

        	try {

        		if(fileInputStream != null){

        			fileInputStream.close();

        		}

        		if(fileOutputStream != null){

        			fileOutputStream.close();

        		}

			} catch (IOException e) {

				e.printStackTrace();

			}

        }

		long end = System.currentTimeMillis();

		System.out.println("视频文件从“from”目录拷贝到“to”文件须要" + (end - start) + "毫秒。");

	}

}

代码执行结果为：

代码1、代码2和代码3复制的是同样的文件，通过对比不难得出结论：：尝试使用文件时，文件拷贝输入和输出流可能是一个更好的办法。