Week 10: Input and Output with Streams

Streams

Sometimes data is written to a file instead of the computer screen. Under Unix and DOS you can sometimes do this using the redirection operators < and >. However sometimes you need a more fine-grained approach that writes only certain data to a file while still putting other data on the screen. Or you may need access to multiple files simultaneously. Or maybe you want to query the user for input rather than accepting it all on the command line. Or maybe you want to read data out of a file that's in a particular format. Or perhaps you want to send data to or read data from a network socket or a URL. In Java all these methods require streams. In fact the System.out object you've been using since class 1 is a stream.

What is a Stream?
The Stream Classes
Where do streams come from?
The InputStream Class
Reading bytes of data
Reading many bytes of data
Counting the available bytes
Skipping bytes
Marking and resetting
Closing Streams
Output Streams
Output Stream Example
Input from Files
Examples of Input from Files
Writing data to Files
Example of Output to Files
Appending data to files
Filter Streams
Filter Stream Classes
Buffered Streams
Data Stream Classes
Print Stream
PushbackInputStream

Files

The java.io.File Class
File Constructors
File Methods
Examples of the File Methods
File Dialogs
Random Access Files
Filename Filters

Readers and Writers

Readers and Writers
The java.io.Reader Class
The java.io.Writer Class
The InputStreamReader Class
The OutputStreamWriter Class
Available Encodings
Writing Text Files
File Reader
Buffering Reads for Better Performance
Line Numbering
Buffering Writes for Better Performance
PrintWriters

Week 10 Exercises

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Last Modified December 10, 1997
Copyright 1997 Elliotte Rusty Harold
elharo@metalab.unc.edu