Javase (20) recursion, Io stream, self-learning character stream

1: Recursion (understanding)

(1) The phenomenon of invoking the method itself in the method definition

Old monks tell stories to little monks, we learn to program

(2) the notice of recursion;

A: To have an exit, or a death recursion

B: Not too many times, or memory overflow

C: Construction method cannot be used recursively

(3) Cases of recursion

A: recursion to find factorial

B: the rabbit Problem

C: Recursive output file absolute path for all specified suffix names under the specified directory

D: Recursively delete directories with content (use caution)

2:io Flow (Master)

(1); O for the operation of data transfer between devices

(2) Classification

A: Flow Direction

Input stream Read Data

Output stream writes out data

B: Data type

BYTE stream

BYTE input stream

BYTE output stream

Character Stream

Character input stream

Character output stream

Attention:

A: If we do not specify according to what points, by default according to the data type of

B: Unless the file is opened in a Windows-brought Notepad we can read it before using a character stream, otherwise we recommend using a byte stream

(3) Fi1eoutputotream Write Data

A: Operation procedure

A: Create a byte output stream object

B: Weekly Write () method

B: Code representation

FileOutputStream fos = new FileOutputStream ("Fos.txt");

Fos.write ("he11o". GetBytes ());

Fos.close ();

C: Issues to be aware of

A: How many things do you do to create a byte output stream object?

B: Why C1ose ()?

C: How to implement the data line wrapping?

D: How to implement the data append write?

(4) Fi1einputstream reading data

A: Operation procedure

A: Create a byte input stream object

B: Call the Read () method

C: Releasing Resources

B: Code representation

Fi1einputstream fis= New Fi1einputstream ("Fos. TXT ");

Mode 1

int by = 0;

while ((By=fis.read ())!=-1) {

System.out.print ((char) by);

}

Mode 2

byte[] bys = new byte[1024];

int len = 0;

while ((Len=fis.read (bys))!=-1) {

Systen.out.print (New String (Bys,0,len));

}

(5) Case: 2 Kinds of implementations

A: Copy A text file

B: Copy Picture

C: Copy Video

(6) Byte buffer stream

A:bufferedoutputstream

B:bufferedinputstream

(7) Case: 4 Kinds of implementations

A: Copy A text file

B: Copy Picture

C: Copy Video

3: Self-taught character stream

IO Stream classification

BYTE stream

InputStream

FileInputStream

Bufferedinputstream

OutputStream

FileOutputStream

Bufferedoutputstream

Character Stream

Reader

FileReader

BufferedReader

Writer

FileWriter

BufferedWriter

Javase (20) recursion, Io stream, self-learning character stream