(1)字节输入流

基类:InputStream

FileInputStream、ByteArrayInputStream、PipedInputStream、BufferedInputStream、ObjectInputStream、FilterInputStream、PushbackInputStream、DataInputStream

(2)字节输出流

基类:OutputStream

FileOutputStream、ByteArrayOutputStream、PipedOutputStream、BufferedOutputStream、ObjectOutputStream、FilterOutputStream、PrintStream、DataOutputStream

(3)字符输入流

基类:Reader

FileReader、CharArrayReader、PipedReader、StringReader、BufferedReader、InputStreamReader、FilterReader、PushbackReader

(4)字符输出流

基类:Writer

FileWriter、CharArrayWriter、PipedWriter、StringWriter、BufferedWriter、OutputStreamWriter、FilterWriter、PrintWriter