How to use properties in a Spring project to configure log4j.xml

Question

I have multiple properties files in my Spring project. The spring context loads these properties and handles property overriding in a convenient manner. Is there a way to take the properties that are available to my Spring configuration XML files (ie. ${myprop}) and use them in a similar fashion in my log4j.xml file? I know that I can pass system properties to log4j using -Dprop=value on startup, but I would prefer having all of the configuration in the properties files in my project. Is this possible?

My app runs in Tomcat.

Answer 1

Try to use this class, after integrating your multiple properties files to one Properties.

public class DOMConfiguratorWithProperties extends DOMConfigurator {

    private Properties propertiesField = null;

    public synchronized Properties getProperties() {
        return propertiesField;
    }

    public synchronized void setProperties(final Properties properties) {
        propertiesField = properties;
    }

    @Override
    protected String subst(final String value) {
        return super.subst(value, getProperties());
    }

    public static void configure(final String filename) {
        new DOMConfiguratorWithProperties().doConfigure(
                filename,
                LogManager.getLoggerRepository());
    }

    public static void configure(
            final String filename,
            final Properties properties) {
        DOMConfiguratorWithProperties configurator = new DOMConfiguratorWithProperties();
        configurator.setProperties(properties);
        configurator.doConfigure(
                filename,
                LogManager.getLoggerRepository());
    }
}