sk. sk. - 29 days ago 18
Java Question

How do I set the timezone in Tomcat for a single web app?

What is the best way to set the time zone in Tomcat for a single web app? I've seen options for changing the command-line parameters or environment variables for Tomcat, but is there a way to set it that is self-contained in the WAR file and not dependent on any Tomcat configuration?

Edit: to reemphasize, I'm looking for a solution that can be contained within a WAR file, not dependent on Tomcat configuration. To put it another way, can one web app be configured to have a different time zone than other apps running in the same Tomcat instance?

Answer

The only way I found is to setup a filter and change the timezone in the filter,

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
        throws IOException, ServletException {
    TimeZone savedZone = TimeZone.getDefault();
    TimeZone.setDefault(webappZone);
    chain.doFilter(request, response);
    TimeZone.setDefault(savedZone);
}

The setDefault() changes the zone for the thread. So everything running in the thread inside the filter will have a different default timezone. We have to change it back because the thread is shared by other apps. You also need to do the same for your init(), destroy() methods and any other thread you might start in your application.

I had to do this because a third-party library assumes default timezone and we don't have source code. It was a mess because this changes log timezone but we don't want log in different times. The correct way to handle this is to use a specific timezone in any time value exposed to end users.

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