1.1 What is IO
We can regard the transmission of data as a flow of data. According to the direction of the flow, based on the memory, it is divided into input input and output output, that is, the flow to the memory is the input flow and the output flow out of the memory.
I/O operations in Java mainly refer to the use of contents under the java.io package for input and output operations. Input is also called reading data, and output is also called writing out data.
1.2 Classification of IO
According to the flow of data, it is divided into: input stream and output stream.
Input stream: a stream that reads data from other devices into memory.
Output stream: A stream that writes data out of memory to other devices.
There are two types of layout data: byte stream and character stream.
Byte stream: The stream of reading and writing data in bytes.
Character stream: A stream of reading and writing data in units of characters.
For clarity, you can draw a picture to illustrate :
