//public BufferedOutputStream(OutputStream out):
//第一种
// FileOutputStream fos=new FileOutputStream("c.txt");
// BufferedOutputStream bos=new BufferedOutputStream(fos);
//等同于下面这个
BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream("c.txt"));
//写入数据
bos.write("hello".getBytes());
//释放资源
bos.close();