How can I specify system properties in Tomcat configuration on startup?

Question

I understand that I can specify system properties to Tomcat by passing arguments with the -D parameter, for example "-Dmy.prop=value".

I am wondering if there is a cleaner way of doing this by specifying the property values in the context.xml file or some other tomcat configuration file. I would like to do this because, first, it is easier to keep track of my properties, and second, I have multiple contexts running and I don't know how I would specify context-specific properties through the -D parameter.

I am using Tomcat version 5.5.

Answer 1

cliff.meyers's original answer that suggested using <env-entry> will not help when using only System.getProperty()

According to the Tomcat 6.0 docs <env-entry> is for JNDI. So that means it won't have any effect on System.getProperty().

With the <env-entry> from cliff.meyers's example, the following code

System.getProperty("SMTP_PASSWORD");

will return null, not the value "abc123ftw".

According to the Tomcat 6 docs, to use <env-entry> you'd have to write code like this to use <env-entry>:

// Obtain our environment naming context
Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");

// Look up our data source
String s = (String)envCtx.lookup("SMTP_PASSWORD");

Caveat: I have not actually tried the example above. But I have tried <env-entry> with System.getProperty(), and that definitely does not work.