Get the server port number from tomcat without a request

Question

Is there any Tomcat API or configuration available which can tell an application (probably on startup), what port its running on without a request?

Imagine a scenario where there are two web applications running in the same Tomcat and one of which need to invoke a web service from the other one. We don't want the request to leave the Tomcat (if you use the Apache server name or absolute URL, the request will go out and come back again and it can go to any instance) and come back in. For that I know the name of the machine but no way to get the port number. I know I can hard code this information but I don't want to do this as I want my war file to be application server agnostic.

I know that we can find it if we have a HTTPServletRequest

This works only for Tomcat 6 and will not work on Tomcat 7

Solution 1

For anybody who is interested in how we solved this, here is the mock code

Server server = ServerFactory.getServer();
        Service[] services = server.findServices();
        for (Service service : services) {
            for (Connector connector : service.findConnectors()) {
                ProtocolHandler protocolHandler = connector.getProtocolHandler();
                if (protocolHandler instanceof Http11Protocol
                    || protocolHandler instanceof Http11AprProtocol
                    || protocolHandler instanceof Http11NioProtocol) {
                    serverPort = connector.getPort();
                    System.out.println("HTTP Port: " + connector.getPort());
                }
            }


        }

Solution 2

With this:

List<String> getEndPoints() throws MalformedObjectNameException,
        NullPointerException, UnknownHostException, AttributeNotFoundException,
        InstanceNotFoundException, MBeanException, ReflectionException {
    MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
    QueryExp subQuery1 = Query.match(Query.attr("protocol"), Query.value("HTTP/1.1"));
    QueryExp subQuery2 = Query.anySubString(Query.attr("protocol"), Query.value("Http11"));
    QueryExp query = Query.or(subQuery1, subQuery2);
    Set<ObjectName> objs = mbs.queryNames(new ObjectName("*:type=Connector,*"), query);
    String hostname = InetAddress.getLocalHost().getHostName();
    InetAddress[] addresses = InetAddress.getAllByName(hostname);
    ArrayList<String> endPoints = new ArrayList<String>();
    for (Iterator<ObjectName> i = objs.iterator(); i.hasNext();) {
        ObjectName obj = i.next();
        String scheme = mbs.getAttribute(obj, "scheme").toString();
        String port = obj.getKeyProperty("port");
        for (InetAddress addr : addresses) {
            if (addr.isAnyLocalAddress() || addr.isLoopbackAddress() || 
                addr.isMulticastAddress()) {
                continue;
            }
            String host = addr.getHostAddress();
            String ep = scheme + "://" + host + ":" + port;
            endPoints.add(ep);
        }
    }
    return endPoints;
}

You will get a List like this:

[http://192.168.1.22:8080]

Solution 3

public void getIpAddressAndPort() 
throws MalformedObjectNameException, NullPointerException,
            UnknownHostException {

        MBeanServer beanServer = ManagementFactory.getPlatformMBeanServer();

        Set<ObjectName> objectNames = beanServer.queryNames(new ObjectName("*:type=Connector,*"),
                Query.match(Query.attr("protocol"), Query.value("HTTP/1.1")));

        String host = InetAddress.getLocalHost().getHostAddress();
        String port = objectNames.iterator().next().getKeyProperty("port");

        System.out.println("IP Address of System : "+host );
        System.out.println("port of tomcat server : "+port);

    }

Solution 4

The server port number doesn't exist. It can have any number of port numbers. So what you're asking doesn't make sense. The port number associated with a specific request does make sense.

Solution 5

These types of servers are designed to be able to listen on (almost) arbitrary ports and to hide these details from the contained applications which normally do not need to know.

The only way is to read the configuration files yourself and have access to the command line arguments that started the server where the configuration files may have been overridden. You have to know a lot about the system you are running on for this to work. There is no way of doing it portably.

Even if there were, there are cases in which it simply does not matter like being behind a NAT, certain firewalls, etc.

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