IO notes (below)--character unit output stream

The previous byte input and output streams can be adapted to be emptied arbitrarily, but in actual use, we mostly use bytes.

First, the inheritance relationship diagram: The
picture is taken from: http://www.cnblogs.com/skywang12345/p/io_01.html

input stream Reader

The top-level object of the character input stream is the Reader (abstract class). There are the following methods:

method	return value	illustrate	Remark
read(char cbuf[], int off, int len)	int	Basic core reading	core, abstract, abstract method
read(java.nio.CharBuffer target)	int	read
read()	int	read
read(char cbuf[])	int	read
skip(long n)	long	skip character
ready()	boolean	Determine if it can be read
markSupported()	boolean	Determine whether tags are supported
mark(int readAheadLimit)	void	mark	Use mark and reset together
reset()	void	reset
close()	void	close stream

in addition:

1. Contains the internal members of protected Object lock; for locking and ensuring synchronization.

output stream Writer

method	return value	illustrate	Remark
write(char cbuf[], int off, int len)	void		core, abstract, abstract method
write(int c)	void	write	---
write(char cbuf[])	void	write	---
write(String str)	void	write	---
write(String str, int off, int len)	void	write	---
append(char c)	Writer	continuous writing	支持append(XXX).append(XXX)
append(CharSequence csq)	Writer	continuous writing	The parameter can be String, support append(XXX).append(XXX)
append(CharSequence csq, int start, int end)	Writer	continuous writing	The parameter can be String, support append(XXX).append(XXX)
flush()	void	situation cache	---
close()	void	closure	---

in addition:

1. 1. Internal members including protected Object lock; are used for locking to ensure synchronization.
   
2. Contains the internal members of private char[] writeBuffer; with its own buffer.
   
3. CharSequence is the interface of String, so append(CharSequence csq) can

input/output stream implementation object

ByteArrayInputStream 和 ByteArrayOutputStream

Input and output streams for character arrays:

name	Superior inheritance relationship	illustrate	core	Remark
CharArrayReader	Reader	input stream of char array	Essence: protected char buf[]
CharArrayWriter	Writer	output stream of char array	Essence: protected char buf[]

Note:
It is a character array itself, which is actually very similar to ByteArrayInputStream and ByteArrayOutputStream.

PipedReader和PipedWriter

Pipeline communication input and output streams:

name	Superior inheritance relationship	illustrate	core	Remark
PipedReader	Reader	input stream for pipe communication	Essence: char buffer[]	Use with PipedWriter
PipedWriter	Writer	output stream for pipe communication	本质: private PipedReader sink;	Use with PipedReader

InputStreamReader和OutputStreamWriter

Character input and output streams:

name	Superior inheritance relationship	illustrate	core	Remark
InputStreamReader	Reader	character input stream	Essence: private final StreamDecoder sd;	Created in the way of new InputStreamReader(InputStream in), converted from byte stream, it is an extension
OutputStreamWriter	Writer	character output stream	Essence: private final StreamEncoder se;	new OutputStreamWriter(OutputStream out)的方式创建，从字节流转换，算是一种扩展

注：
想进行字符串的话，更加的扩展是PrintWriter，new PrintWriter(new FileOutputStream(file))的方式使用。

FileReader和FileWriter

文件字符输入输出流：

名称	上级继承关系	说明	核心	备注
FileReader	InputStreamReader	文件字符输入流	本质： 完全是调用的InputStreamReader
FileWriter	OutputStreamWriter	文件字符输出流	本质: 完全是调用的FileOutputStream

BufferedReader和BufferedWriter

缓冲字符输入输出流：

名称	上级继承关系	说明	核心	备注
BufferedReader	Reader	缓冲字符输入流	本质： private char cb[]	有readLine()，可以很方便的读取一行
BufferedWriter	Writer	缓冲字符输出流	本质: private char cb[]	注意，write写入后，不会马上反应，调用flush()清空缓存后反应