Java application inside tomcat?

I have a 开发者_如何学编程standalone java application which uses java based TCP NIO to collect some information from various clients (not on web/HTTP but through some indigenously developed middleware). Now I have to develop a front-end for the users to perform a lot of querying through HTTP. So is there a way to put this application inside tomcat, so that servlets can invoke required functions on this application ??? The thing is it has to listen on that middleware outside tomcat too and at the same time service servlets inside tomcat. How to do this ??

Putting this application outside tomcat and using RMI is an option but I don’t want to do that. Can embedding tomcat inside my application is an option ???

---

The brand-new Tomcat 7 has Embedded version for download.

---

Tomcat is big. You should try to embed Jetty, which is meant in order to make it possible.

http://jetty.codehaus.org/jetty/

---

I don't know about embedding Tomcat, but you can embed a servlet container inside your application using embedded Jetty. If what you want is to add an HTTP interface to an existing server, I think that's the way to go.

It also should be perfectly workable to launch your server's TCP listening components from a standard servlet in Tomcat. Then the servlet can call methods in your existing application directly, while it continues to listen to its usual TCP ports.

A third option is to write a servlet that just talks to your existing server in the same way other clients do.

---

The way you want to go, is to have an embedded web server to your existing application since you just need a little bit of web functionality.

Going the other way is possible. You can use servlet listeners to get started and stopped, and you need to take great care of any thread you start since Tomcat have no idea they exist.

---

As Traroth said, embedding Jetty is a much better option than doing the same with Tomcat. You have an example and a small tutorial in the Jetty website: http://docs.codehaus.org/display/JETTY/Embedding+Jetty

You can always open the ports and listen manually if the requests aren't complicated.

---

Have you considered going the other way? That is embedding your application inside a web application?

Using spring you can instantiate your web application and then inject in into the appropriate web classes (e.g. struts2 actions).

This way you can deploy your web application into any web server that is preconfigured separate from your application.

---

If you do have to use Tomcat, you're best just making your application as a .war file which when Tomcat is ran will deploy your code. This can then talk to any RMI/middleware you like.

---

I'm not sure I understand your comment regarding memory spaces.

At a very basic level you have two choices:

1. Run your appication and the web application in the same virtual machine.

2. Run your application and the web application in a different virtual machine

If you take approach 1, you will be able to get instances of your applications classes from the servlets and call methods on them.

1. Embed tomcat / jetty inside your application. You will start your application normally through its main method. After starting your app you will need to create instances of the tomcat / jetty classes which will start up their own threads.
2. Embed your application inside a war file to be deployed on tomcat / jetty. Similar to the previous option instead you will need to start your application from a context listener.

If you prefer approach 2; start tomcat / jetty and deploy your web app and separately deploy your application. You'll now have two jvms running. To communicate between these two processes you'll have to use some form of socket communication: OutputStream/InputStream over sockets; RMI; JMX; JMS etc.