jakarta ee - How to include values from .properties file into web.xml?

Question

I need to include some values from a file.properties into the WEB-INF/web.xml something like this:

<param-name>uploadDirectory</param-name>
<param-value>myFile.properties['keyForTheValue']</param-value>

I'm currently working with this:

• JBoss
• JEE5

Answer 1

You can add this class, that add all properties from your file to JVM. And add this class like context-listener to web.xml

public class InitVariables implements ServletContextListener
{

   @Override
   public void contextDestroyed(final ServletContextEvent event)
   {
   }

   @Override
   public void contextInitialized(final ServletContextEvent event)
   {
      final String props = "/file.properties";
      final Properties propsFromFile = new Properties();
      try
      {
         propsFromFile.load(getClass().getResourceAsStream(props));
      }
      catch (final IOException e)
      {
          // can't get resource
      }
      for (String prop : propsFromFile.stringPropertyNames())
      {
         if (System.getProperty(prop) == null)
         {
             System.setProperty(prop, propsFromFile.getProperty(prop));
         }
      }
   }
}  

in web.xml

   <listener>       
      <listener-class>
         com.company.InitVariables
      </listener-class>
   </listener>  

now you can get all properties in you project using

System.getProperty(...)

or in web.xml

<param-name>param-name</param-name>
<param-value>${param-name}</param-value>