JavaIO流-流的分类

一、流的分类
* 1.操作数据单位：字节流、字符流
* 2.数据的流向：输入流、输出流
* 3.流的角色：节点流、处理流
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二、流的体系结构（常用）
* 抽象基类                节点流               缓冲流（处理流的一种）
* InputStream            FileInputStream  (read(byte [] buffer))           BufferedInputStream  (read(byte [] buffer))
* OutputStream           FileOutputStream (write(byte [] buffer,0,len))    BufferedOutputStream (write(byte [] buffer,0,len))
* Reader                 FileReader (read(char [] cbuf))                   BufferedReader  (read(char [] cbuf)/readLine())
* Writer                 FileWriter (write(char [] cbuf,0,len))            BufferedWriter  (write(char [] cbuf,0,len))