Java - how to get IP address automaticallly in JNLP file?

Question

In the JNLP file how do I get the IP address automatically? Example:

<?xml version="1.0" encoding="utf-8"?> 
<jnlp spec="1.0+" codebase="GET ip address here automatically" href="Test.jnlp">

instead of manually setting the address to: codebase="http://10.10.10.1/"

score 3 · Answer 1 · answered Dec 05 '11 at 16:47

3

The JNLP file is a static resource. To do something like that you would need to use some sort of dynamic server side technology, such as JSP, to represent the JNLP.

answered Dec 05 '11 at 16:47

laz

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score 1 · Answer 2 · edited May 23 '17 at 11:45

If you host your JNLP file in a Java Web Container (e.g. Tomcat) instead of normal HTTP server (e.g. Apache Web Server), you may use JNLP Servlet provided by Sun https://stackoverflow.com/a/7593088/418439. Some interesting variables are $$codebase, $$site (see code below). For instance, $$site in JNLP file will be replaced by the hosting machine ip address and its port (E.g. http://10.10.10.1:8080)

private String specializeJnlpTemplate(HttpServletRequest request, String respath, String jnlpTemplate) {
    String urlprefix = getUrlPrefix(request);
    int idx = respath.lastIndexOf('/'); //
    String name = respath.substring(idx + 1);    // Exclude /
    String codebase = respath.substring(0, idx + 1); // Include /
    jnlpTemplate = substitute(jnlpTemplate, "$$name",  name);
// fix for 5039951: Add $$hostname macro
jnlpTemplate = substitute(jnlpTemplate, "$$hostname",
              request.getServerName());
    jnlpTemplate = substitute(jnlpTemplate, "$$codebase",  urlprefix + request.getContextPath() + codebase);
    jnlpTemplate = substitute(jnlpTemplate, "$$context", urlprefix + request.getContextPath());
    // fix for 6256326: add $$site macro to sample jnlp servlet
    jnlpTemplate = substitute(jnlpTemplate, "$$site", urlprefix);
    return jnlpTemplate;
}

score 1 · Accepted Answer · answered Dec 05 '11 at 16:42

1

It can't do that.

You can add a DNS entry for 10.10.10.1, and put the hostname in that field instead of the IP address, but it's just XML - there's no way to call a method from that line to run code and figure out what IP address it should connect to.

answered Dec 05 '11 at 16:42

jefflunt

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Thank you very much. I am sorry I just realized that the question I posted is very dumb. All I had to do was remove codebase completely for it to work. I find that JAVA documentation is all over the place and that is sometimes I ask stupid questions. – jadrijan Dec 05 '11 at 16:49
No worries. We all see things differently, and what might be obvious to some, is confusing to others. Happens to me all the time. – jefflunt Dec 05 '11 at 16:58

score 1 · Answer 4 · answered Dec 05 '11 at 16:43

1

Have a look at the official documentation about relative addresses, which might help (you can avoid specification of the server address altogether): http://docs.oracle.com/javase/6/docs/technotes/guides/jweb/applet/codebase_determination.html

answered Dec 05 '11 at 16:43

Chris Dennett

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Thank you very much. I am sorry I just realized that the question I posted is very dumb. All I had to do was remove codebase completely for it to work. I find that JAVA documentation is all over the place and that is sometimes I ask stupid questions. – jadrijan Dec 05 '11 at 16:49

Java - how to get IP address automaticallly in JNLP file?

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