Question

I am reading a properties file from the Tomcat\conf\somename.properties directory using

String demo = System.getProperty("catalina.base") +
                  File.separator + "conf" + File.separator + "somename.properties";

This is working perfectly fine with Tomcat. But, there can be scenario where client may use any other server like Glassfish or Websphere, in that case I won’t be able to get System.getProperty("catalina.base").

How should I solve it properly? I’m able to do that using ResourceBundle but for that I have to keep my properties file in my build, which I don’t want. I just want to read my properties file from outside my build.

Answer 1

There are basically two ways.

1. Just add its path to the runtime classpath so that you can get it from the classpath the usual way. In case of Tomcat, you can add external folders to the runtime classpath by specifying it in the shared.loader property of /conf/catalina.properties. E.g.

   shared.loader = ${catalina.home}/conf

   Or better, don’t be server-specific

   shared.loader = /path/to/folder

   Other servers also supports adding external folders to the classpath, consult their documentation.

   This way you’ll be able to get an InputStream of it from the classpath as follows:

   InputStream input = Thread.currentThread().getContextClassLoader().getResourceAsStream("/config.properties");
   Properties properties = new Properties();
   properties.load(input);
   // ...
   

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2. Add another server-independent system property yourself, you can set as a VM argument.

   -Dconfig.location=/path/to/folder

   In case of Tomcat, you can set it as JAVA_OPTS environment variable, or edit the catalina.bat startup file or edit the Windows Service settings (when it’s installed as Windows Service), etc. Other servers supports similar constructs as well.

   This way you can obtain it as follows

   File file = new File(System.getProperty("config.location"), "config.properties");
   InputStream input = new FileInputStream(file);
   Properties properties = new Properties();
   properties.load(input);
   // ...
   

   ---

Either way you choose, when distributing your application, you should document it properly so that the serveradmin can configure it accordingly.

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Unrelated to the problem, the ResourceBundle is not the right way to read configuration properties files. It’s intented for localized content for internationalization.