How to read a properties file outside my webapp context in Tomcat

Question

I have this requirement that my webapp needs to read from a properties file outside the Tomcat webapps directory, for example from $CATALINA_HOME/properties/myapp.properties. I have tried several things but so far no luck

Solution 1

There are multiple approaches .

1. Use an Environmental variable
2. Use a System Property
3. Set it as a Application Context Param in Web.xml

Heres a sample ,that showsOption 1 and Option 2

try {

    //Use Any Environmental Variable , here i have used CATALINA_HOME
    String propertyHome = System.getenv("CATALINA_HOME");           
    if(null == propertyHome){

        //This is a system property that is  passed
        // using the -D option in the Tomcat startup script
        propertyHome  =  System.getProperty("PROPERTY_HOME");
    }


    String filePath= propertyHome+"/properties/myapp.properties";

    Properties property = new Properties();         
    property.load(SystemTest.class.getClassLoader().getResourceAsStream(filePath));
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

Solution 2

I prefer the option to configure via Tomcat context descriptors.

These XML-documents are placed into the folder tomcat/conf/Catalina/<host>/*.xml

This refers to: Externalizing Tomcat webapp config from .war file

Solution 3

In our project that we config the path of file as vm arguments which will stored in the tomcat properties and in the code, use System.getProperty(the parameter you config) to get the path and read the properties file, then get the results.

Comments

[Fernando]

Thank you! I used your second approach with System Property "catalina.home" This is exactly what I needed!

[Andrew Niken]

Yeah, but in case Tomcat and if I need read file somewhere in class .... implements ServletContextListener {} I got WAR related path ! Is it possible something using for example SPRING to get path outside of WAR ? file:d:/my/path/toFile.log