21 October 2008 ~ 1 Comment

Implementing UDP Server using Apache MINA

Network Programming

In my last post we created a UDP client using Apache MINA. Lets turn the table and implement the Server side. Let's see how using Apache MINA reduces the effort to create a UDP Server.

Steps to create a UDP Server using java.net API's

  1. Create a Socket and listen for incoming connection
  2. Process each packet in a separate thread :-) (I hate this, unfortunately need this to have high processing rate)
  3. Parse and process the request and optionally send response (Lets omit this to keep things simple)
Lets see how to achieve the same using Apache MINA
  1. Create a NioDatagramAcceptor
  2. Add an IoHandler
  3. Bind and make application ready to receive
That's it :-)
Before we dive into the code, lets see some assumption made to run this
  • Our protocol is carrying Strings in UDP packet
  • We shall not do any transformation on the packets received. We shall just dump the content
The Handler

 


The Handler is in its basic form. Our only method of interest is messageReceived. Since we know that we are getting "String" message without any transformation, we could easily create a new string from the bytes received. A wonderful thing to note about this API is the parameter "message". This makes the API generic enough to cater to any kind of objects. If we had used a ProtocolCodec in the chain and had transformed the byte[] into a custom Object, we would have type-casted message to that object.

That's all in the handler.

 

The Server
Lets see the main Server code

 

 

The Server is even simpler than client :-)
We create an instance of NioDatagramAcceptor and add our custom handler to it. We then bind to the port desired. Here I have made it bind to the default port, code can be customized to bind to any port desired.

So what does 31 does. There is wonderful description of this option at http://www.unixguide.net/network/socketfaq/4.5.shtml
The main function is pretty simple. The Server is ready. You can run it, using the Client from the post Implementing UDP Client using Apache MINA

References

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One Response to “Implementing UDP Server using Apache MINA”

  1. shiva 21 November 2008 at 11:26 am Permalink

    hi, ashish…..
    how do you do?….

    im devlping TFTP server with MINA, i have a prob…( describing here)

    i want to send a packet and i need to for ACK,
    if and only if ACK comes then i have to send next packet and so….
    ( here I must wait for ACK)

    I tried( even now trying) but not geting… Hope u can do it easily,
    If you can plz try and send me…..

    thanq…….


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