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From David Smith <d...@cornell.edu>
Subject Re: access files from jsp
Date Tue, 29 Apr 2008 18:39:02 GMT
So... the "remote file" is available to the local system on a network 
drive. That's a fun one. There are a couple of different ways to do this.

1. Using Windows fileshares

Let me preface this by saying *I've* never done this. The few times I've 
had a tomcat server on a Windows machine, it only ever accessed local 
files. There are people on the list with way more experience than I have.

As I understand it, as long as tomcat is running under a user account 
that has privileges to read the remote file, you could use a UNC path 
with java standard file access classes and methods to read the file. The 
mapped drive letter wouldn't work unless tomcat was only running while 
you are logged in. In a jsp, this could be done with a scriptlet:

<!-- import your classes at the top of the jsp.... -->
<jsp:scriptlet>
try {
FileInputStream remoteFileReader = new FileInputStream( 
"\\\\remoteServer\\archive\\files\\myFile.txt" ) ;
// do something with the file
} catch ( Exception e ) {
// do something if the access fails
} finally {
try {
remoteFileReader.close() ;
} catch ( Exception e ) {}
}
</jsp:scriptlet>

It should be mentioned the system account most services run under by 
default does not have any privilege to access remote files via UNC path, 
so you'll have to customize your tomcat installation a little. ... Or 
always be logged into the system and have it running as you which isn't 
the most ideal method.

2. Using a webserver on the remote system

This I have done and it's more platform independent. Your jsp can 
request it from the remote server using standard taglibs:

(note standard.jar and jstl.jar must be in your webapp's WEB-INF/lib 
directory)

<!-- import the core taglib from jstl at the top of the file. Docs for 
the jstl taglib can help with this -->

<c:import url="http://remoteSystem.dns.com/http/path/to/file.txt" 
var="fileContents" />
<!--.... Do something with the file contents, it'll be available in the 
fileContents page context attribute.... -->


--David

henry human wrote:
> Thanks David,
> I try to clarify my situation.
> I have a JSP running in local computer in tomcat. This
> JSP should read from a remote machine. The files are
> under d:\archive\files. These directory which provide
> a repository functionality could not be transfer
> somewhere else. The files “must be” saved there. 
> 1) Scennario one: The remote machine does not hava e
> webserver
> 2) Scenario two: a tomcat is running on remote
> computer 
>
> My questions:
> 1) Do I need the webserver at all to access remotely
> the files?
> 2) Is it poosile to access the data on d:\archive…
> without to put them in a webserver directory or not?
> If no, do I need configuration for the webserver (f.i.
> tomcat)to allow access to the files from outside? 
>
>
> --- David Smith <dns4@cornell.edu> schrieb:
>
>   
>> Here's the picture you painted in the original email
>> and I based my 
>> answer on:
>>
>> 1. You have a jsp file on a tomcat server which
>> needs to read 
>> information from a remote system
>> 2. The system containing the remote file has a
>> webserver you could put 
>> the file in.
>>
>> The c:import tag is a java standard tag library
>> (JSTL) tag used to 
>> import data form locations outside the jsp.  In this
>> case, I'm saying 
>> you could request the file from the remote
>> webserver.  Google is your 
>> friend if you'd like more information.
>>
>> If I've misunderstood your environment, please
>> provide a *lot* more 
>> detail -- specifically more information regarding
>> the system the remote 
>> file reside's on (does it have a web server?).
>>
>> --David
>>
>> henry human wrote:
>>     
>>>   
>>>       
>>>> Seems to me the simplest is the c:import tag and
>>>>     
>>>>         
>>> sorry,I don't understand what you mean, could you
>>>       
>> tell
>>     
>>> more detailed. Maybe a little code code, a sample,
>>>       
>> etc
>>     
>>>   
>>>       
>>>> fetch the file via http
>>>>     
>>>>         
>>> how?? 
>>>   
>>>       
>>>> -- just my two cents.   You know more about your
>>>> architecture and what's 
>>>> available than any of us.
>>>>     
>>>>         
>>> ??
>>> what
>>> should be configured in tomcat ?
>>> Do you mean that i do not need tomcat at all for
>>>       
>> this
>>     
>>> scenario?
>>> I think it is not possible to read from the 
>>> hard disc directories f.i. d:\archive\files
>>>       
>> without
>>     
>>> helps of a web server ?
>>>
>>> I am appreciated, if you get a sample, more
>>>       
>> details!
>>     
>>>   
>>>       
>>>> --David
>>>>
>>>> henry human wrote:
>>>>     
>>>>         
>>>>> Once again because there was a mistake in the
>>>>>       
>>>>>           
>>>> first
>>>>     
>>>>         
>>>>> email :
>>>>>  i am about to read from a JSP the data at a
>>>>>  remote computer. At remote computer is tomcat
>>>>>  running. the files are stored in 
>>>>>  remote computer at
>>>>>  d:\archive\files 
>>>>>  The port 80 is also accessible.
>>>>>  Please tell me, what should be 
>>>>> configured in tomcat to 
>>>>>  be able to access the files
>>>>>  ?
>>>>>  
>>>>> I am thankful for any hint
>>>>>
>>>>>
>>>>>
>>>>>      
>>>>>       
>>>>>           
> __________________________________________________________
>   
>>>   
>>>       
>>>>> Gesendet von Yahoo! Mail.
>>>>> Mehr Möglichkeiten, in Kontakt zu bleiben.
>>>>>       
>>>>>           
>>>> http://de.overview.mail.yahoo.com
>>>>     
>>>>         
>>>>>       
>>>>>           
> ---------------------------------------------------------------------
>   
>>>   
>>>       
>>>>> To start a new topic, e-mail:
>>>>>       
>>>>>           
>>>> users@tomcat.apache.org
>>>>     
>>>>         
>>>>> To unsubscribe, e-mail:
>>>>>       
>>>>>           
>>>> users-unsubscribe@tomcat.apache.org
>>>>     
>>>>         
>>>>> For additional commands, e-mail:
>>>>>       
>>>>>           
>>>> users-help@tomcat.apache.org
>>>>     
>>>>         
>>>>>   
>>>>>       
>>>>>           
>>>> -- 
>>>> David Smith
>>>> Network Operations Supervisor
>>>> Department of Entomology
>>>> Cornell University
>>>> 2132 Comstock Hall
>>>> Ithaca, NY 14853
>>>> Phone: (607) 255-9571
>>>> Fax: (607) 255-0940
>>>>
>>>>
>>>>
>>>>     
>>>>         
> ---------------------------------------------------------------------
>   
>>>   
>>>       
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>>>>
>>>>
>>>>     
>>>>         
>>>
>>>       E-Mails jetzt auf Ihrem Handy.
>>> www.yahoo.de/go
>>>
>>>
>>>       
> ---------------------------------------------------------------------
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>>
>>     
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>>     
>
>
>
>       __________________________________________________________
> Gesendet von Yahoo! Mail.
> Mehr Möglichkeiten, in Kontakt zu bleiben. http://de.overview.mail.yahoo.com
>
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>   


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