Re: Servlet init

From:

Juha Laiho <Juha.Laiho@iki.fi>

Newsgroups:

comp.lang.java.programmer,comp.lang.java.help

Date:

Thu, 15 Jun 2006 20:20:30 +0000 (UTC)

Message-ID:

<e6sfed$362$3@ichaos2.ichaos-int>

"Sameer" <dolpheen@gmail.com> said:

The init method for a servlet is as follows:

public void init(){
       try {
           Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
           connection =
DriverManager.getConnection("jdbc:odbc:library");
       } catch(ClassNotFoundException cnfe) {
           System.err.println("Error loading driver: " + cnfe);
       } catch (SQLException ex) {
           ex.printStackTrace();
       }
   }

The Stack Trace does not print in the browser and we also do not have
access to HttpServletResponse object.
Then how it is possible to display an error message in the client's
browser if database connection fails?

init() will be called before the first time a service method of the
servlet is called, and init() is called without any reference to
any inbound request that there might be. The error message will
(possibly) go to one of the log files.

One thing you could do here is to throw an UnavailableException,
and perhaps catch that with an error-handler page to provide a more
user-friendly error message.

Or, as was suggested in another message, have init() set a flag
variable within the servlet object to signify failure in jdbc
initialization, and show an error message based on that flag.
--
Wolf a.k.a. Juha Laiho Espoo, Finland
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