SAMS Teach Yourself Programming with Java™ in 24 Hours, FOURTH EDITION

Reading and Writing Configuration Properties

Java programs are more versatile when they can be configured using command-line arguments, as you have demonstrated in several applications created in preceding hours.

The java.util package includes a class, Properties, that enables configuration settings to be loaded from a file.

The file can be read like other file sources in Java:

• Create a File object that represents the file

• Create a FileInputStream object from that File object

• Call load() to retrieve the properties from that input stream

A properties file has a set of property names followed by an equals sign (“=”) and their values. Here's an example:

username=lepton
lastCommand=open database
windowSize=32

Each property has its own line, so this ...