I'm currently developing a web server based on sockets for a web game.
The client will be based on Java applet.
Is it possible to use Apache Tomcat server for this mission?
If it is possible, could you recommend us a step by step guide for how to configure it?
Do you think that we should use alternative server for that?
Will it be easier to implement this using servlets (http requests) and Google Application Engine?
I think you have to write your own connector and protocol handler for tomcat if you need another protocol than http.
In this case try Apache Mina.
I don't know anything about Servlets and Tomcat, but you can simply start the server as a standalone Java program, opening a ServerSocket to listen on the port. On each connection, split off a new Thread with will read from the new Connection.
For greater scalability, use nonblocking IO and a selector instead of a separate thread for each connection.
Related
I'm developing an Android app using a server side for computations and message handling. I need to work with push notifications, so I decided to go with Socket and ServerSocket.
For now, my server side is just a pure JAVA code that receive requests and open sockets accordingly. Is there any framework for my purpose? And how should I run my server side app on a remote server, should I create a runnable jar or is there any other way?
You can use Apache MINA, which is a socket framework with useful features like NIO, session management, SSL and other filter support.
Using a reliable framework means you spend less time writing boilerplate code.
Yes, you can create a runnable jar and create a bat/sh script to run on your server. Read this article for more information on packaging applications.
What are the possible ways in which Java Swing Application which is running on client side can communicate with server?
I've read that JSP can be used in web pages to communicate between server and client.But, is it possible to use JSP with Swing application? if so, how? It would be helpful, if it is demonstrated with simple login form. Thanks.
Any client-side application, whether it be a java swing app or otherwise, can certainly communicate with any server (assuming no network limiting architecture -- firewalls and whatnot). Your options are numerous
Raw sockets
Any one of the myriad of network protocols.
HTTP/HTTPS
FTP
SCP
et. al.
It depends on what protocol, services and applications are available on the server to connect with.
HTTP/HTTPS is very common. You'll need to manually create HTTP requests and send them to the server (assuming the server is a web server).
I am planing to develop JavaScript client application that will connect to Java server using websocket. Server should handle many connected clients.
After some reading I found out websocket single thread. This is not good if I want to run databases query that can block everything for a while.
What I am thinking about is to opening separated websocket for each JavaScript client. One socket is listening for new connection and when connection is established creates some unique id. After that opens new websocket and send id to client using listener socket. When client received id close first socket and connect to new one.
What do you think, is it good solution? Maybe I am missing something?
Spring 4 gives you the chance to use a thread pool. The documentation is here:
http://docs.spring.io/spring/docs/current/spring-framework-reference/html/websocket.html
You could use Akka to manage all the concurrency and thread management for you. Or you could use the Play Framework that already builds on Akka and that supports WebSocket quite nicely. With Play you can choose between Java and Scala on the server side.
You should use NodeJS on the server to handle the socket i/o. You can connect to it via your javascript client apps, and then make calls to your Java based API. NodeJS is non blocking (async) and you should be able to leverage your existing Javascripting skills to quickly build a Node app. You could even use a full MEAN stack to build the client/server app. http://meanjs.org/ or http://mean.io/#!/ are two popular places to start.
I have not worked with HTTP post/get before, my up coming project in my office is based on http post/get in java. Its basically client - server based application. the client will post some info and I need to get that info and process the string and vice-verse. this project has to be developed on J2SE. You can assume this some thing like a JMS queue message processing stuff. I googled for the info but most of the information was for web application, mine should work like a message queue. Can someone explain me how to do this or point me where I can get some useful info.
Thanks
Arun
Well, if you don't need to specifically use strict HTTP, and you need to just use Java SE (and not Java EE, which rules out Servlets, JSPs, JMS, etc), then you need to probably investigate ServerSocket and Socket classes.
Server
Your server would need to listen on a TCP port (say, port 8080) - usually you would pick a port number between 1025 and 65,535, however if you are attempting to use an already defined service that has a default port, then use that. Note however, that on unix, in order to listen on any port below 1024, I believe you need to be root. Traditionally, port 80 is used for HTTP.
To listen on this port, you would need something like this in your code:
ServerSocket srvSocket = new ServerSocket(8080);
Socket socket = srvSocket.accept();
This pretty much the most basic code that would cause your application to wait until something connected to port 8080. Once connected, you could obtain both an InputStream and OutputStream for your connected client, by interrogating the returned socket object, allowing you to read content from the client, and inserting these requests in a queue. This queue could be then processed by some other Thread.
Client
In order for your client to connect to the server, you would need to use something based on the following example:
Socket connection = new Socket("server.domain.com", 8080);
OutputStream output = connection.getOutputStream();
You would then write your request to the server into the OutputStream (and read from the InputStream returned from getInputStream() if you expected a response)
The code supplied is pretty basic, but it should give you a rough idea of how to proceed. You can even use this method if you wanted to use real HTTP, however it might be a better idea to use some premade library if that was the case (although its probable that you're not going to require all functionality defined in the HTTP spec itself).
Anyway, I hope that provides you a good starting point from which to build.
Jetty is a popular web server, designed to easily be embedded in an application.
Its HTTP server component can run inside your application and respond to requests by dispatching to your custom code.
Jetty also features an HTTP client that you can use on the client side to send requests.
This is a rather big topic and I won't be able to post a complete guide, but Jetty's documentation is generally of very high quality and should be a good starting point.
I suggest you start with learning the basics of HTTP protocol. This article is a good starter. After you understood the basics follow the this article on how to programatically communicate (read/write) with HTTP servers. After that Google is your friend.
If you weren't restricted to J2SE, you could use Servlets for managing the POST/GET methods of HTTP. Evaluate if it is possible, otherwise you'd be reinventing the wheel
I also have a mainly SE background. On the client side, writing get/post is pretty easy. Or you can Google to find source code. I found that using REST was straightforward and understandable. On the server side, there are many options and I have very limited experience. I wrote the server using standard JEE6 and it wasn't too painful, but sounds like that is not an option for you.
I have to design a client/server system emulated on a website running Ruby on Rails that should work like this:
a page is requested by a web browser and once it's opened the server can push messages to it
I know this is not possible "naturally" but I was thinking of a sort of "java applet" that is running on that page, listening on a port for messages to be sent by the hosting server. This should be done opening a sort of a socket that listens on some port where the server can connect to send its messages.
Can this be done? Do I have to develop a java server thread or can I simply address the client applet via it's ip address and port and use any web service connection from the server?
thanks,
Luca
Comet is definately what you want. Depending on your needs, you can host your own comet server, or use a SaaS solution, such as WebSync On-Demand (disclaimer: I work there). Using the SaaS stuff, you get server-push capabilities without having to actually run your own comet server.
The easiest way to do that is to use Javascript to emulate the push mechanism. Polling in regular intervals using AJAX is sufficient in most cases. Have also a look at Comet.
An alternative to using a java applet may be to use a combination of javascript and an approach known as Comet. In a nutshell, Comet is a way to enable server push over HTTP. I'm not really a ruby on rails guy, but a quick google search for ruby on rails and comet nets a fair amount of useful information.
have you looked at juggernaut
If you want go the applet route, you need to make the connection from applet to the same server where the web page is served. The applet can't listen. Once the TCP connection is established, it's a 2-way channel, you can pull or push as long as your protocol allows it. This is how it's done with most Applet-based chat clients.
More and more people are simply using long polling in Javascript. It's pretty involved to get a reliable long polling system running, I would suggest you to use a framework. For example,
http://cometdproject.dojotoolkit.org/