How do I implement a web application with a Servlet that is listening on a port for socket connections?
+2
A:
I assume you don't mean the front-door HTTP connection, which you get for free with the servlet container... But if you want to add, say, an admin service you could create a listener thread that sets some global state in the servlet. Note that this is not considered kosher (and I believe may even violate the servlet standard).
Greg Harman
2009-08-30 18:16:52
I have a remote client and would not like to use HTTP but TCP sockets to connect to my server, therefore I would like my servlet to create some kind of serverSocket and listen for client requests for socket connections.
Kevin Boyd
2009-08-30 18:23:14
Servlets are very specifically an HTTP standard. If you don't want HTTP, you shouldn't use servlets - just write a custom client/server application, as Helen suggets.
Greg Harman
2009-08-30 18:43:02
Greg Harman
2009-08-30 18:48:04
+2
A:
Not totally sure what you want to achieve, but you can have a look at client/server programming if that's what you need. Other than that, you could implement your web application as normal but change the default port to whatever suits your need.
Helen Neely
2009-08-30 18:19:31
Refer to my written to Greg, I need something similar to client/server programming but can I implement it with servlets or would I have to go some other way.
Kevin Boyd
2009-08-30 18:25:50
+2
A:
Having the servlet open ServerSockets is a bad code smell. This is primarily because it is the container's responsibility to manage sockets (among other resources like worker threads, sessions etc).
That said, I do not think you need a servlet in the first place. Unless you want to access some of the container's services, it would be better if you use a J2SE application to manage ServerSockets.
Vineet Reynolds
2009-08-30 18:29:44
What would I then need to implement this? Any code example? I have looked in client/server example posted above. Is that the way to go?
Kevin Boyd
2009-08-30 18:36:57
"It Depends!!". It is easy to come up with a server application using J2SE, as long as you dont botch up anything related to what a J2EE/JEE container provides out of the box. If you ever have to deal with transaction management, state management, thread pools etc., take a look at a HTTP based message exchange format, and use servlets. Eventually, it is depends on what you need your server to do.
Vineet Reynolds
2009-08-30 18:42:12