I have a client software that is written in C++/C# and a database. Now I don't want the client to access the database directly, so I thought about placing an application server in the middle. This one should get a short request from the client, ask the database for new data, do some filtering (that can't be done in sql) and then return the data to the client.
My search for this kind of software brought me to Glassfish or Tomcat but my problem in understanding is, that these always want to talk http with html/jsp. Because most of my data is encrypted anyways, I don't need such plain text protocols and would be totally happy with something that just takes a byte stream.
On the other hand would it be nice to have a server handle the thread pool for me (don't want to implement all that from scratch).
After more than a day of searching / testing I'm even more confused than at the beginning (ejb, beans, servlet, websocket, ... so many things to google before understanding just the simplest tutorials).
TL;DR: how do I get Tomcat/Glassfish to just open a socket and create a new thread for every request, without any HTML/CSS/JSP involved?
Jetty and Tomcat are so called servlet container and thus primarly targeted at HTTP exchanges. Glassfish is an application server that uses a servlet container as one of its modules. I would stop thinking in that direction - that's all more like web applications and web services - some levels too high what you are asking for.
I think you should more look into sth. like Netty which is merley a "high performance protocol" server. Take a look at the documentation here (even some sort of tutorial there which might fit your use case).
GlassFish is an "enterprise application server", targeting the Java EJB specification. That's surely overdone for your purpose. You can give Tomcat a try. It is a "servlet container", targeting Java Servlet specification. Servlets have one purpose: listening to an incoming URL (request), executing Java code and returning a response, usually over HTTP.
For sure, you may start your own (plain) ServerSocket, for example using a ServletContextListener (which will be started once your application starts). But you should go for a higher protocol to send the data, like Hessian and Burlap, which is implemented in both, Java and C++ and easy to set up.
Related
Anyone has expirience on having Jruby project running on Jboss (using torquebox or whatever) with an ability to communicate with another "japps" not on the same jboss where jruby app is, i.e. some java project on another jboss?
I know there is an torque-messanging but dunno if it's possible to communicate with external(out of jruby-app's jboss) app?
Best practices are welcomed.
Thanks in advance.
P.S. placing that other app on the jboss where jruby app is not acceptible solution.
I can recommend you to use Thrift and build communication via them.
Thrift have generator for both your needed languages (Java and JRuby) and provide good and fast communication.
UPDATED:
Thrift is RPC (remote procedure call) framework developed at Facebook. In detail you can read about it in Wiki.
In few word to save you time, what it is and how to use it:
You describe you data structures and service interface in .thrift file(files). And generate from this file all needed source files(with all need serialization) for one or few languages(what you need). Than you can simple create server and client in few lines
Using it inside client will be looks like you just use simple class.
With Thrift you can use what protocol and transport used.
In most cases uses Binary or Compact protocol via Blocked or Not-blocked transport. So network communication will be light and fast + with fast serialization.
SOAP(based on XML on HTTP) packages, its in few times bigger, and inappropriate for sending binary data, but not only this. Also XML-serialization is very slow. So with SOAP you receive big overhead. Also with soap you need to write (or use third-party) lib for calling server(tiny network layer), thrift already made it for you.
SMTP and basically JMS is inappropriate for realtime and question-answer communication.
I mean if you need just to put some message in queue and someone sometime give this message and process it — you can (and should) use JMS or any other MQ services(Thrift can do this to, but MQ architecture is better for this issue).
But if you need realtime query-answer calls, you should use RPC, as protocol it can be HTTP(REST, SOAP), binary(Thrift, ProtoBuf, JDBC, etc) or any other.
Thrift (and ProtoBuf) provide framework for generate client and server, so it incapsulate you from low level issues.
P.S:
I made some example in past https://github.com/imysak/using-thrift (communication via Thrift Java server + Java Client or node.js client), maybe it will be useful for someone . But you can found more simple and better examples.
Torquebox supports JMS. The gem you specified torquebox-messaging allows for publishing and processing of HornetQ messages on the local JBoss AS server/cluster that the JRuby app is running in. I don't think it currently supports connecting to remote servers.
Using this functionality in your JRuby app you could then configure your Java app on another server to communicate with HornetQ running in the JBoss AS that the JRuby app is running on.
Alternatively you could always implement your own communication protocol or use another Java library - you have access to anything Java you want to run from JRuby.
You can use Web Services or JMS for that
I'm starting to develop what should become a client-server Application using Hibernate, Spring and Eclipse RCP (for the client). This is the first time I'm designing an application from the beginning so I'm just making my first steps.
I have set up Spring on both client and server using RMI for remoting (but I wouldn't mind using something else if there was a clear advantage). So right now I'm able to call exposed services of the server from different clients to get information from the database. What I haven't done is get any kind of authentication in place, so basically the server just answers to the different clients without knowing anything about them, there is not concept of a session yet. Of course this has to change since I need different user to have different roll and so on, but right now the problem I'm facing is getting the server to notify the client when certain thing happen.
My idea to solve this problem was to have a queue of events at the Server and have the clients get them every 3 second or so. The server would then identify the client by it's session token and send the appropriate events. Yet my partner in this project is concerned that this technique (polling) might waste too much bandwidth unnecessarily.
So to bring it to the point. What are the standard techniques for a server to notify a client about changes using Spring? Please notice that I'm not developing a web application and that this is only intended to be used withing a private network. That is one of the difficulties I've been facing: every single tutorial about Spring security or remoting assumes you are making a web application, but I really don't want to get lost into the details of Spring MVC and web applications in general.
Any resources would be appreciated. A good and long tutorial on the matter would be great.
EDIT: Hmm, it looks like JMS might be what I'm looking for.
As I understand, the issues you are facing is identifying a client in request and correlate different client request i.e. have something like a session.
Spring also support RMI over HTTP protocol (Using Hessian and its own HTTP Invokers). Check out this link (Section 17.3). Now once you have transport as HTTP, it has inherent Basic Authentication and session which can be leveraged to get around the issues you are facing.
This is just a pointer. I would be curious to know how eventually you resolved your problem.
could you please give me a sample code on how an Http Server(Java) receives the request of a client(android)? I mean the client sends the request via Httppost, how the server takes the content of these requests in order to see the context and reply? I am trying to built a chat application.
Thank you in advance!
The server-side of HTTP is usually implemented using the protocol stack provided by a web container. You would then implement your application's server-side as servlets. There are numerous tutorials on this.
If that's the way you want to proceed, look at one of the standard web containers; e.g. Tomcat, Jetty, Glassfish, etc. The source code for all of these is available for you to browse, though I should warn you that they are all complicated under the hood.
Assuming that your HTTP service is going to be delivering JSON or XML (rather than HTML) to clients, you may want to look into using a RESTful framework.
Have a look at ServerSocket. Keep in mind that accept() blocks and, as you will probably run it in a service, you will want to time it out and check for the completion of the service. That should probably run in its own thread as should the responders to requests.
From there, you can open input and output streams to receive the request and write the response. There are any number of packages that can help you with the interaction, or you can roll your own, but it doesn't seem like you've done a lot of homework. Perhaps some searching, reading, and more specific questions would more you along more quickly.
I have a website (python/django) that needs to use a load of Java resources that may or may not be on the same server. Therefore I am writing a mini webserver in Java that will receive a request and then when processing is finished, POST some data back to a url on the site.
I have got the java code receiving connections on sockets and responding with some simple HTML.
My problem is that I will POST data to the Java server and that code needs to act on the data. How do I go about reading the data that is posted in the HTML request, if it is even possible. If not, is there any other way you would do this.
If you think I am going about this in completely the wrong way then please tell me and I will consider another method, but after conversing with some Java developers, this seemed like the best way for what I was doing.
Thanks
You probably don't need to write a http server yourself, just use some lightweight java web server/servlet container like jetty or simple
and looks here if you still want to know how to parse a http POST request http://www.jmarshall.com/easy/http/#postmethod
In your case I probably wouldn't work with low level socket connections.
I recommend you to use a servlet container with some sort of webservice or maybe only a simple servlet depending on your needs. With a servlet you can easily access the POST data, process it and return something to the caller.
If you don't want to use a stand alone servlet container like Tomcat you can try an embeddable servlet container like Jetty or winstone servlet container.
If you need something more sophisticated you can use some webservice technology like JAX-RS or JAX-WS. This allows you to provide a fully featured API for your Java resources in an easy way.
I have to design a distributed application composed by one server (developed in Java) and one or more remote GUI clients (Swing application with windows).
As stated before the clients are Swing GUI application that can connect to the server in order to receive and send data.
The communication is bidirectional (Server <=> Clients).
Data sent over the network is mainly composed by my domain logic objects.
Two brief examples: a client calls the server in order to receive data to populate a table inside a window; the server calls client in order to send data to refresh a specific widget (like a button).
The amount of data transmitted between server and clients and the frequency of the network calls are not particularly high.
Which technology do you suggest me for the server-clients communication?
I've in mind one technology suitable for me but I would like to know your opinions.
Thanks a lot.
The first technology that came to my mind was RMI - suitable if you're communicating between java client and java server. But you may get difficulties if you want do switch the client technology to - say - a webinterface.
I would go with RMI but implement the whole architecture using Spring framework. This way it is independent of technology used and can be switched to other ways of communication (such as HTTP or other ) with almost no coding.
UPDATE: And Spring will allow you to have none of RMI specific code.
I believe sockets should do the trick. They are flexible and not especially hard to code/maintain. Most entry level programmer should also be able to maintain them. They are also fast and adapt to any kind of environment.
Unless, your server is going to be off-site or you expect to have firewall issues. In that case, web services are the way to go since your basic communication happens through port 80.
I would second msparer's suggestion of RMI, except I would just use EJB3 (which uses RMI as the communication protocol). EJB3 are very easy and even if you don't use the other feaures EJB gives you (e.g., security) you can still leverage Container Managed Transactions (CMT). It really does make development easy.
As for the server->client communication, you would probably want to use JMS. Again, using EJB3 this is pretty e3asy to do with annotations. The clients will subscribe to the message service and receive update notifications from the server.
And yes, I am currently working on an application that does this very thing. Unfortunately we are using EJB2.1. Still, it is my opinion that this is where EJBs really shine. Using EJBs in a web app is frequently overkill, but in a distributed client/server app they work very well.
You can try using ICE http://www.zeroc.com for establishing server-client connection.