isFile () to determine whether the file
isDirectory () judgment is not a folder is to see is not a directory
getName () to get the name of the file
getParent () to get the parent directory
getPath () Get file full path
length () Gets the size of the file
lastModified () Gets the last modified event
listFiles () returns all subfolders return value is an array class file file []
the delete () delete function
exist (); returns a Boolean to determine the presence of class
d.mkdirs (); create multi-level directory
d. createNewFile (); create the file

如何在文件不存在的情况下创建目录？
exist()
d.mkdirs()
d.createNewFile()##
这三个一起配合使用即可

Coding related

Byte and Character

Computer character can not be artificially divided understand I do not know 0 a This is
the byte computer only know the binary digits 0 and 1

字符利于人来阅读，但是不利于计算机阅读

Encoding type

ASCII codeA byte Byte eight small bits to store common English and characters represent up to 256 characters, it is clearly not enough

Spreading code (add byte)
EG:
ISO8859 ----- Western European
GBK --------- (the most commonly used more than 20,000 Chinese characters)
GB18030 ---- is GB series represents the most complete coding seventy thousand Chinese characters and characters
Traditional Chinese big5 ------------

即使这样了但还是不能共通，所以，有了Unicode
Unicode
All over the world, including characters include
goal is to continue to expand to include global language
encoding scheme
UTF-8: compatible with ASCII, the use of variable-length character, 1-4 characters stored in the character of small letters (such as a, b, c) on a ; Chinese characters with a 2.

UTF-16: 2-4 variable length

UTF-32: with four bytes. Anyway, 32bits certainly big enough, but not economic. So UTF-8 is the most commonly used

ANSI code
Windows on non-Unicode encoding default
when the system is simplified Chinese GBK, Traditional Chinese system is Big5.
The default is to use Notepad ANSI send each other so you save files in different countries in the region are likely garbled.

The input and output streams

Abstract base class stream

Byte stream

InputStream
OutputStream

Character stream

Reader
Writer

巧记：结尾的时候，字节stream，字符er

the difference

Mode of operation is basically the same but different things returned. Next, an input stream by way of example:

int read();

Remove the single byte and returns an int. Since it is only the bytes 8bit range 0-255
So when you can not read Chinese characters will flow in bytes. Read the tail -1 is returned
when you output will be like this:

	int c = f.read();
	System.out.println((char)c);

int read(byte[] b);

Read more bytes are read method returns a value of how many
, but if you read 100 each, and finally only 40, it will repeatedly read 60, read from the reciprocal of 100

	byte[] buffer = new byte[1024]
	int len = System.in.read(buffer);

	read读的所有IO操作都带着exception的异常处理或者抛出！

Note here that is byte at a time to read, so if the input stream will come in the carriage length will also read one more than the actual

int read(byte[] int off, int len);

Select Location

skip(long n);

How many skips

int available();

Tell you how much flow there is also something to read

mark();

Where is read to make a mark

reset();

Back to the last time that mark where the mark is valid only played once

close();

Be sure to turn off! ! ! ! Otherwise, two lines of tears! ! !

Reader

Basically the same but the difference in taking a bunch of drops of water droplets and take a sip of water and a bunch of small saliva meaning.
(Or, meal times, before one meter one meter or meter pile a bunch of rice, now directly get a bowl, a bowl of a bowl on the more convenient)

int read();

But the return value of a character stream can be a very big
Java int 2 bytes in a range on the great 0-60000 in more than a

其他操作基本一样

Output stream

OutputWriter / Writer

op.write(byte b)

This byte writes to go inside

write(byte[] b)
write(byte[] b, int start , int len)

the same

但是对于Writer类。由于是字符，所以可以String形式。
像write(String s)这样来。

But the abstract base class itself can not create objects so the need for packaging design

Entity class

Node Class

Direct file read and write

		FileOutputStream out = new FileOutputStream("文件地址或者File对象");
		out.write(buf)        //buf 是个byte[]  意思就是一次写入这么多个字节
		out.close();            //关了

A document file ------------- B
the middle of this connecting channel is ------

Wrapper class

Conversion class

Byte character conversion type, such as encoding "UTF-8"

Transformation class InputStreamReader
when reading a file, byte character into Java can understand

The OutputStreamWriter
the Java class characters converted into text input bytes

E.g:

		fis = new FileInputStream("c:/temp/abc.txt");
		isr = new InputStreamReader(fis,"UTF-8");

A (Java) ======= ---- B (the target file)

- refer to the ordinary encoding
== means into a UTF-8
so that from B to A then it would be appreciated by Java UTF-8 of

Decoration

Filtering package based on the existing flow on
a more powerful functions to read and write

E.g:

		DataOutputStream out = new DataOutputStream(
		new BufferedOutputStream(
		new FileOutputStream(file)));

DataInputStream DataOutputStream for encapsulating the data stream and
may output a direct Int 4 bytes of a double byte to be automatically converted into eight
so you out with this thing directly out.writeInt (i) this method is substantially directly put inside type rather than a byte

Another example:

		fis = new FileInputStream("c:/temp/abc.txt");
		isr = new InputStreamReader(fis,"UTF-8");
		br = new BufferedReader(isr);

BufferedInputStream BufferOutputStream cache byte stream
is say he wanted to open in memory read and write such a buffer zone can be faster
BufferedReader, BufferedWriter cache character stream
later with Buffer can have in.readLine such usage
but read here () methods are read default string delimiter is a space

A JavaBean

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Private letter concerns

[Lehr] personal understanding of Java's IO