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javavelocity

Use InetAddress in Velocity template

I'm trying to display the IP address of the current machine in a Velocity template. I assumed I could do this simply by including the line 

$java.net.InetAddress.getLocalHost().getAddress()

in the template.

However, the line is not evaluated and is displayed as is; the log shows a null reference:

Null reference [template 'login.vm', line 43, column 11] : $java.net.InetAddress.getLocalHost().getAddress() cannot be resolved.

What did I do wrong?

Solution

  • According to the documentation it should be done in the following way:

    1) add desired class to the context:

    Template t = ve.getTemplate("q44153836.vm");    

VelocityContext context = new VelocityContext();
context.put("InetAddress", java.net.InetAddress.class);

StringWriter writer = new StringWriter();
t.merge(context, writer);

    2) use this name for retrieving its methods in the template:

    $InetAddress.getLocalHost()

    Also note, that $InetAddress.getLocalHost().getAddress() will return your byte array which can not be displayed as ip address. It will display array's toString() value. Better to use $InetAddress.getLocalHost().getHostAddress().