IO streams Summary and Classification:
A: The concept
IO stream for processing data transfer between devices
java operations on the data stream by way of
java class for IO operations in stream packet
The flow is divided into two flows by: the input and output streams
According to the operation type is divided into two streams:
Byte stream: byte stream can operate any data, since any data in a computer is stored in the form of bytes
Character stream: a stream of characters can only be operated pure character data, more convenient
B: IO stream common parent class
Abstract parent class byte stream:
InputStream
OutputStream
Abstract parent class character streams:
Reader
Writer
C: IO program writing
Before use, import classes package IO
When in use, perform IO exception handling
After use, the release of resources
FileIputStream:
read () reads one byte
read () method returns a value Why is int?
read () method reads a byte is why returns int, instead of a byte
Because the input stream of bytes can operate any type of file, such as pictures you audio, etc., these are the underlying documents stored in binary form, if each read returns byte, there are likely to encounter when read the middle 11111111
11111111 then this is the type of byte-1, our program is not encountered -1 will stop reading the following data is less than school, so receiving an int when read, if 11111111 will be supplemented in front 0 24 gather the 4 bytes, the byte type int -1 becomes the 255 type, which can ensure that the entire data read, that is of type int -1 and ends labeled
FileOutputStream：
write () method to write a byte time
FileOutputStream追加：
Copy of the picture:
FileInputStream read
FileOutputStream to write
Copies of the byte array available () Method:
Drawbacks: it is possible to run out of memory
Definition of small array:
Defining the standard format small array:
BufferedInputStream and BufferOutputStream copy:
A: Buffer thought
A first array of the byte stream read speed significantly faster than the time to read and write a byte of the velocity
This is added to the buffer effect of such an array, when java itself in the design,
Also take into account such a design, it provides a byte buffer flow
B：BufferedInputStream
BufferedInputStream a built-in buffer (array)
Reading a byte from the BufferedInputStream
BufferedInputStream will be a one-time read from the file 8192
Until all of the buffers are used, only to re-read from the file 8192
C：BufferOutputStream
BufferOutputStream also a built-in buffer (array)
When the program write byte, not written directly to the file stream, first written to the buffer
Know when the buffer is full, BufferOutputStream will put the data in the buffer is written to a one-time file
D：Demo
E: small array of read-write and read with Buffered Which is faster?
If the definition of a small array size is 8192 bytes and then compared Buffered
Definition of small arrays will be slightly better, because read and write operations to the same array
The two arrays are operated Buffered
The difference between flush and close methods:
flush () method
Buffer used to refresh, refresh can write again
close () method
Close to release the flow of resources, methods, if it is with close stream object buffer () will not only close the stream, but also flushes the buffer before closing the stream, after closing can not write
Byte stream read and write Chinese:
Byte stream read Chinese problem
Chinese stream of bytes read when there could read half Chinese, resulting in garbled
Write byte stream problem of Chinese
Byte byte stream directly operated, it is necessary to write a Chinese string into a byte array
CRLF write write ( "\ r \ n" .getBytes ());
Standard flow exception handling code for version 1.6 and earlier:
Standard flow exception handling code for version 1.7:
Image Encryption:
Copy files:
Input data is copied to the file: