缓冲流复制文件(java)

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;




public class Demo01_BufferedOutputSream {

	
	public static void main(String[] args) throws IOException {
		//copy01();//用时194ms
		//copy02();//用时38943ms
		copy03();//用时4ms
		
	}
	
	
	public static void copy01() throws IOException
	{
		FileOutputStream fos = new FileOutputStream("C:\File\11\22\myCopy.avi");
		FileInputStream fis = new FileInputStream("C:\File\myCopy.avi");
		BufferedOutputStream bos = new BufferedOutputStream(fos);
		BufferedInputStream bis = new BufferedInputStream(fis);
		long star = System.currentTimeMillis();
		
		int len = 0;
		while((len = bis.read()) != -1){
			bos.write(len);
		}
		long end = System.currentTimeMillis();
		System.out.println("用时" + (end - star) + "ms");	//225ms
		
		bos.flush();
		bos.close();
		bis.close();
	}
	
	
	public static void copy03() throws IOException
	{
		FileOutputStream fos = new FileOutputStream("C:\File\11\22\myCopy.avi");
		FileInputStream fis = new FileInputStream("C:\File\myCopy.avi");
		BufferedOutputStream bos = new BufferedOutputStream(fos);
		BufferedInputStream bis = new BufferedInputStream(fis);
		long star = System.currentTimeMillis();
		
		int len = 0;
		byte[] bytes = new byte[102415];	//测试发现当byte数组为5为数时速度最快，当加到6位数时，其速度反而下降了
		while((len = bis.read(bytes)) != -1){
			bos.write(bytes,0,len);
		}
		long end = System.currentTimeMillis();
		System.out.println("用时" + (end - star) + "ms");	//225ms
		
		bos.flush();
		bos.close();
		bis.close();
	}
	
	
	public static void copy02() throws IOException
	{
		FileOutputStream fos = new FileOutputStream("C:\File\11\22\myCopy.avi");
		FileInputStream fis = new FileInputStream("C:\File\myCopy.avi");
		long star = System.currentTimeMillis();
		
		int len = 0;
		while((len = fis.read()) != -1){
			fos.write(len);
		}
		long end = System.currentTimeMillis();
		System.out.println("用时" + (end - star) + "ms");
		fos.close();
		fis.close();
	}
}