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copyFileByBytes:47ms

copyFileByDataOutputStream:31ms

copyFileByBufferedOutputStream:49ms

//排除時(shí)間誤差,三種方法基本一樣.

	public?static?void?copyFileByBytes(File?from,?File?to)?throws?IOException?{
		if?(!from.exists())?{
			System.out.println("文件不存在");
		}
		if?(!from.exists())?{
			System.out.println(from?+?"不是文件");
			//?throw?InterceptorOperations
			//?throw?IORInterceptor;
		}
		FileOutputStream?fos?=?new?FileOutputStream(to);
		FileInputStream?fis?=?new?FileInputStream(from);
		byte[]?buf?=?new?byte[1024?*?1024];
		int?b;
		while?((b=fis.read(buf))?!=?-1)?{
			fos.write(buf,?0,?b);
//			fos.flush();
		}
		fos.flush();
		fos.close();
		fis.close();
	}

	public?static?void?copyFileByDataOutputStream(File?from,?File?to)
			throws?IOException?{
		if?(!from.exists())?{
			throw?new?IllegalArgumentException("文件:"?+?from.getAbsolutePath()
					+?"不存在");
		}
		if?(!from.exists())?{
			throw?new?IllegalArgumentException(from?+?"不是文件,可能是文件夾");
			//?throw?InterceptorOperations
			//?throw?IORInterceptor;
		}
		DataOutputStream?dos?=?new?DataOutputStream(new?FileOutputStream(to));
		DataInputStream?dis?=?new?DataInputStream(new?FileInputStream(from));

		int?i;
		byte[]?buf?=?new?byte[1024?*?1024];
		while?((i?=?dis.read(buf,?0,?buf.length))?!=?-1)?{
			dos.write(buf,?0,?i);
			
		}
		dos.flush();
		dos.close();
		dis.close();
	}

	public?static?void?copyFileByBufferedOutputStream(File?from,?File?to)
			throws?IOException?{
		if?(!from.exists())?{
			throw?new?IllegalArgumentException("文件:"?+?from.getAbsolutePath()
					+?"不存在");
		}
		if?(!from.exists())?{
			throw?new?IllegalArgumentException(from?+?"不是文件,可能是文件夾");
			//?throw?InterceptorOperations
			//?throw?IORInterceptor;
		}
		BufferedOutputStream?bos?=?new?BufferedOutputStream(new?FileOutputStream(to));
		BufferedInputStream?bis?=?new?BufferedInputStream(new?FileInputStream(from));

		int?i;
		byte[]?buf?=?new?byte[1024?*?1024];
		while?((i?=?bis.read(buf,?0,?buf.length))?!=?-1)?{
			bos.write(buf,?0,?i);
			
		}
		bos.flush();
		bos.close();
		bis.close();
	}