【Java.IO】I/O 流的类体系结构

所有位于java.io包内的stream类型分别都继承自一下四种抽象stream类型：

	字节 Bytes Stream	字符 Character Stream
Input Stream	InputStream	Reader
Output Stream	OutputStream	Writer

InputStream

InputSteam的基本方法：

Methods  

Modifier and Type	Method and Description
int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
abstract int	read() Reads the next byte of data from the input stream.
int	read(byte[] b) Reads some number of bytes from the input stream and stores them into the buffer array b.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n) Skips over and discards n bytes of data from this input stream.

灰色的代表节点流。白色的代表处理流。

FileInputStream

从一个文件中获取字节数据；通常用于读取原始的字节数据文件，如image data；对与字符型文件，推荐采用FileReader。

PipedInputStream

实现了pipe的概念，主要在线程中使用。管道输入流是指一个通讯管道的接收端。

一个线程通过管道输出流发送数据，而另一个线程通过管道输入流读取数据，这样可以实现两个线程间的通讯：

BypteArrayInputStream

StringBufferInputStream

不推荐使用StringBufferInputStream，此类不能将字符正确的转换为字节。

从字符串创建流的最佳方法是采用StringReader。

SequenceInputStream

把多个InputStream合并成为一个InputStream，并使它们像单个输入流一样。每个输入流依次被读取，直到到达该流的末尾，然后关闭这个流并自动切换到下一个输入流。

OutputStream

OutputStream的基本方法：

Methods  

Modifier and Type	Method and Description
void	close() Closes this output stream and releases any system resources associated with this stream.
void	flush() Flushes this output stream and forces any buffered output bytes to be written out.
void	write(byte[] b) Writes b.length bytes from the specified byte array to this output stream.
void	write(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to this output stream.
abstract void	write(int b) Writes the specified byte to this output stream.

灰色的代表节点流。白色的代表处理流。

FileOutputStream

像File或FileDescriptor输出数据。

PipedOutputStream

管道输出流是指一个通讯管道的发送端。一个线程通过管道输出流发送数据，另一个线程通过管道输入流读取数据，实现两个线程的通讯。

参见PipedInputStream

ByteArrayOutputStream

Reader

Reader的基本方法如下：

Methods  

Modifier and Type	Method and Description
abstract void	close() Closes the stream and releases any system resources associated with it.
void	mark(int readAheadLimit) Marks the present position in the stream.
boolean	markSupported() Tells whether this stream supports the mark() operation.
int	read() Reads a single character.
int	read(char[] cbuf) Reads characters into an array.
abstract int	read(char[] cbuf, int off, int len) Reads characters into a portion of an array.
int	read(CharBuffer target) Attempts to read characters into the specified character buffer.
boolean	ready() Tells whether this stream is ready to be read.
void	reset() Resets the stream.
long	skip(long n) Skips characters.

灰色的代表节点流。白色的代表处理流。

CharArrayReader

与ByteArrayInputStream，实现一个可用作字符输入流的字符缓冲区。

StringReader

与StringBufferInputStream对应，其源为一个字符串的字符流。

FileReader

与FileInputStream对应。

PipedReader

与PipedInputStream对应。

Writer

Writer的基本方法如下：

Methods  

Modifier and Type	Method and Description
Writer	append(char c) Appends the specified character to this writer.
Writer	append(CharSequence csq) Appends the specified character sequence to this writer.
Writer	append(CharSequence csq, int start, int end) Appends a subsequence of the specified character sequence to this writer.
abstract void	close() Closes the stream, flushing it first.
abstract void	flush() Flushes the stream.
void	write(char[] cbuf) Writes an array of characters.
abstract void	write(char[] cbuf, int off, int len) Writes a portion of an array of characters.
void	write(int c) Writes a single character.
void	write(String str) Writes a string.
void	write(String str, int off, int len) Writes a portion of a string.

灰色的代表节点流。白色的代表处理流。

CharArrayWriter

与ByteArrayOutputStream对应。

StringWriter

无与之相对应的以字节为导向的stream

FileWriter

与FileOutputStream对应

PipedWriter

与PipedOutputStream对应