Before we plunge into learning about readers and writers, let us take a slight detour from pure input and output
(while still remaining in the
package) to learn about files.
Dealing with files is an essential prerequisite for being able to use readers and writers.
In this module, you will learn how to:
Manipulate files separately from their contents
Find out what files already exist and how to create new ones
Determine information about a file such as its name and size
Use a random access file and how it differs from a sequential access file
You will also learn about directories, how to move around in them, how to switch from one to another, and how to list their contents.
On the far left of the diagram are the utility methods
readAllBytes, readAllLines, and the write methods, designed for simple, common cases.
To the right of those are the methods used to iterate over a stream or lines of text, such as
- newInputStream and
These methods are interoperable with the java.io package. To the right of those are the methods for dealing with ByteChannels, SeekableByteChannels, and ByteBuffers,
such as the newByteChannel method. Finally, on the far right are the methods that use FileChannel for advanced applications needing file locking or memory-mapped I/O.