java 復制壹個指定文件夾下的指定文件 到另壹個指定文件夾下

下面是我學習過程中總結的幾個復制文件的方法，代碼如下：

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?BufferedStreamCopyFiles?{

public?static?void?main(String[]?args)?throws?IOException?{

/**

?*?***有四個方法,但建議用demo1,demo2;因為demo3需要創建數組,?如果文件大,光創建數組就需要很多時間;demo4壹定也不要用,

?*?效率非常慢.

?*/

demo1();

demo2();

demo3();

demo4();

}

public?static?void?demo1()?throws?FileNotFoundException,?IOException?{

FileInputStream?fis?=?new?FileInputStream("d:\\1.mp3");

FileOutputStream?fos?=?new?FileOutputStream("d:\\01.mp3");

int?len?=?0;

byte[]?buf?=?new?byte[1024];

while?((len?=?fis.read(buf))?!=?-1)?{

fos.write(buf,?0,?len);

}

fis.close();

fos.close();

}

public?static?void?demo2()?throws?IOException?{

FileInputStream?fis?=?new?FileInputStream("d:\\1.mp3");

BufferedInputStream?bufis?=?new?BufferedInputStream(fis);

FileOutputStream?fos?=?new?FileOutputStream("d:\\02.mp3");

BufferedOutputStream?bufos?=?new?BufferedOutputStream(fos);

int?len?=?0;

while?((len?=?bufis.read())?!=?-1)?{

bufos.write(len);

}

bufis.close();

bufos.close();

}

//?不建議這種方式

public?static?void?demo3()?throws?IOException?{

FileInputStream?fis?=?new?FileInputStream("d:\\1.mp3");

FileOutputStream?fos?=?new?FileOutputStream("d:\\03.mp3");

byte[]?buf?=?new?byte[fis.available()];

fis.read(buf);

fos.write(buf);

fos.close();

fis.close();

}

public?static?void?demo4()?throws?IOException?{

FileInputStream?fis?=?new?FileInputStream("d:\\1.mp3");

FileOutputStream?fos?=?new?FileOutputStream("d:\\04.mp3");

int?ch?=?0;

while?((ch?=?fis.read())?!=?-1)?{

fos.write(ch);

}

fos.close();

fis.close();

}

}