IO2:FileInputStream/FileOutputStream--java28(02/23/2016)
InputStream和Reader是所有输入流的基类。InputStream(典型实现:FileInputStream)intread()intread(byte[]b)intread(byte[]b,intoff,intlen)Reader(典型实现:FileReader)intread()intread(char[]c)intread(char[]c,intoff,intlen)程序中打开的