1、         IO包中的类层次
                        ┌BufferedInputStream
                        ├DataInputStream
              ┌FilterInputStream┼LineNumberInputStream
              ├FileInputStream └PushbackInputStream
              ├ByteArrayInputStream
     ┌InputStream──┼PipedInputStream
     │        ├SequenceInputStream
     │        ├StringBufferInputStream
     │        └ObjectInputStream ┌BufferedOutputStream
     │         ┌FilterOutputStream┼DataOutputStream
  Object┤         ├FileOutputStream └PrintStream
     ├OutputStream──┼ByteArrayOutputStream
     ├File       ├PipedOutputStream
     ├FileDescriptor └ObjectOutputStream
     ├ObjdecStreamClass
     ├RandomAccessFile
     └StreamTokenizer

Reader            InputStream
   ├BufferedReader      BufferedInputStream
   │  └LineNumberReader  LineNumberReader
   ├CharArrayReader     ByteArrayInputStream
   ├InputStreamReader     (none)
   │  └FileReader     FileInputStream
   ├FilterReader       FilterInputStream
   │  └PushbackReader   PushbackInputStream
   ├PipedReader        PipedInputStream
   └StringReader       StringBufferInputStream

  Write             OutputStream
  ├BufferedWriter       BufferedOutputStream
  ├CharArrayWriter       ByteArrayOutputStream
  ├OutputStreamWriter     (none)
  │  └FileWriter       FileOutputStream
  ├FilterWriter         FilterOutputStream
  ├PrintWriter         PrintStream
  ├PipedWriter         PipedOutputStream
  └StringWriter         (none)

04-19 15:53