Java.io定义的I/O类如下表所示：
| BufferedInputStream | BufferedOutputStream | BufferedReader | BufferedWriter | ByteArrayInputStream | ByteArrayOutputStream | CharArrayWriter | Console | DataInputStream |
| DataOutputStream | File | FileDescriptor | FileInputStream | FileOutputStream | FilePermission | FileReader | FileWriter | FilterInputStream |
| FilterOutputStream | FilterReader | FilterWriter | InputStream | InputStreamReader | LineNumberReader | ObjectInputStream | Writer | OutputStream |
| ObjectOutputStream | ObjectStreamClass | ObjectStreamFile | PipedReader | PipedInputStream | PipedOutputStream | PipedWriter | Reader | PrintStream |
| PrintWriter | StreamTokenizer | StringReader | StringWriter | RandomAccessFile |
Java 中基于流的I/O以4个抽象类为基础：InputStream，OutputStream，Reader 和 Writer。InputStream 和 OutputStream 用于字节流，Reader 和 Writer用于字符流。一般而言，当与字符或字符串打交道时，应该使用字符流类，而在与字符和其他的二进制对象打交道时，应该使用字节流类。
原文：http://www.cnblogs.com/hoojjack/p/4761896.html