The very point of using servlets is to be able to communicate over port 80 which
is open on most firewalls. We've developed here a book viewer (a book is a list
of buys and sells on a symbol) that is updated in real time as it changes on the
trading system. The viewer is an applet and communicates with servlet using
URLConnection. This product is currently in its beta stage and has real clients
(behind firewalls) test driving it. So far this works like a charm.
The only limitation is the number of concurrent sessions that the web servers
are able to handle. I checked the Volano reports which suggest great numbers
but the more limiting factor seems to be the web server. If anyone has any
experience in squeezing sessions out of a web server (we're running Apache at
this point but can switch if someone has good numbers) I'd much appreciate it.
How are Java applets different from Java applications in their communicating
with servlets? They both have to make a URLConnection to the web server, make a
request and wait and read a response. What exactly is your problem with making
a Java applet work through proxy?
d.
"Shekhar, Jayant" wrote:
> I have also been doing Applet-Servlet communication seriously. I confirm
> Bo's findings.
>
> I works well on:
>
> * Intranet.
> * Servlet container and the Client have public IP address.
> * Dialup connections, where the Client has a dynamic IP address.
> * jdk1.2 plugin. Haven't tested with jdk1.3.
>
> It doesn't seem to work thru:
>
> * Firewall or proxies.
>
> Most of the references in the archives and elsewhere talk about making Java
> applications work thru proxies. None of them talk about making Java applets,
> where you do not know the proxy server, work thru proxies. Any inputs would
> be very helpful.
>
> Thanks,
> Jayant.
>
> -----Original Message-----
> From: Bo Xu [mailto:[EMAIL PROTECTED]]
> Sent: Friday, November 10, 2000 9:44 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Applet-servlet communication does not work on internet.
>
> Hiroshi Kasamatsu wrote:
>
> > Applet-servlet communication does not work on internet.
> > I have been making efforts to find clues,but I cannot see the light yet.
> > I tried some URL connections,but only to fail.
> > The remnant clue I expect is how to select doPost,doGet.
> > *******************************************************
> > 1.
> > Applet side: Servlet side:
> > doGet(....)
> > write object -----------> read object
> > read object <----------- write object
> > *********************************************************
> > 2.
> > Applet side: Servlet side:
> > doPost(....)
> > write object -----------> read object
> > read object <----------- write object
> > *********************************************************
> > I used doPost, or No2,because data is sent.
> > But I also tried No1,but both to fail. One point I worry about is to
> > include read and write within a doPost method.
> > What does not work applet-servlet communication on internet?
> >
> > Hiroshi Kasamatsu
> > [EMAIL PROTECTED]
> >
>
> Hi :-) from several emails in Servlet-List and my work:
>
> 0
> * if you first write something in Applet, then in Servlet,
> service/doPost
> will be invoked.
> * if you first read something in Applet, then in Servlet,
> service/doGet
> will be invoked.
> * so you can only override service in your Servlet class if it is
> possible.
>
> 1
> from my work, it can work in Internet, I have test the following:
> * Servlet container has public IP, its Internet connecting is
> T1/ADSL/ISDN
> * client of my Servlet class:
> # has public IP, its Internet connecting is ISDN
> # dialup user from sprint.ca
> # pure-IE5.0 and pure-NN4.7.
>
> 2
> I remember there are several emails in Servlet-List about the problem of
> Applet-Servlet Communication in the following enviroment:
> * firewall
> * VPN
> * Java Plugin 1.2/1.3 ?
>
> but I am not sure, please check the Servlet Archive - Aug/Sep , 2000 :-)
>
> Bo
> Nov.10, 2000
>
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--
David Mossakowski [EMAIL PROTECTED]
Programmer 212.310.7275
Instinet Corporation
"I don't sit idly by, I'm planning a big surprise"
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