Configuring A .Properties File In App Engine

Configuration settings for an application should never be hardcoded; instead, they should be configured through a separate properties file.

A properties file looks like this:

#This is a comment

The # symbol denotes a comment, while keys are separated from values with an = sign.

You can read this file into a Java application by using the following code. It reads in a properties file named located within the /WEB-INF/ folder (putting your properties files in /WEB-INF/ also keeps them private):

InputStream app_properties_stream = this.getServletContext().getResourceAsStream("/WEB-INF/");
Properties app_properties = new Properties();
//This will throw a NullPointerException if the properties file cannot be found, 
//and an IOException if an error occurs while reading.

From here you can retrieve values by calling:

String value = app_properties.getProperty("key");