关于java IO流

一定要关流！一定要关流！一定要关流！

private static void copyFile() {        File file = new File("D://1.rar");//源文件        InputStream is  = null;        OutputStream os= null;        BufferedInputStream bis = null;        BufferedOutputStream bos = null;        try {            is= new FileInputStream(file);            os = new FileOutputStream("D://2.rar");//目标文件            bis = new BufferedInputStream(is);            bos =new BufferedOutputStream(os);            byte[] b = new byte[1024*1024*300];            int len=0;            while((len=bis.read(b))!=-1){                bos.write(b,0,len);//一定要这样写才好            }            bos.close();            bis.close();        } catch (Exception e) {            e.printStackTrace();        }    }