How to check if a server has disconnected a socket

Hi.

Can anybody help me with the following?

I'm using java.net.Socket to connect to a server. The socket is part of a
client application, and I connect to the server at startup. The application
should be able to handle a lost connection due to a restart of the server or
any other reason. Is it a way to check if the socket connection is still
connected or if the connection has been reset?



Jarle

 

Yes.

If reading from or writing to the streams associated with the Socket
indicates EOF, the connection has been broken and you can (attempt to)
reconnect.

Or, if you are using a java.nio.channels.Selector, the channel will
become ready for reading or writing when the connection breaks. Note
that you still need to actually read or write to determine whether EOF
has been reached.

/gordon

 

Hi,
The only way to know if the connection is alive is to write on the
socket. However depending on your protocol sometimes you're not able to
write on the socket to check the connection (for example if you are waiting
for a response, you will never be aware of this connection loose), this is
why you can set the KEEP_ALIVE option that will check the connection every 2
hours. From my experience, the methods "boolean isBound()" and "boolean
isConnected()" does not give an accurate information if you have connected
the socket once (it seems to be normal since with tcp you can't be aware of
a connection loose unless you are in the two case I was speaking about
before).
This thread discuss of this issue:
http://forum.java.sun.com/thread.jsp?forum=11&thread=539297
Hope this will help,

Olivier

 

Thanks!
The postings in that thread explained a lot.

Jarle