Amit - java.util.HashMap allows null values whereas java.util.Hashtable
does not allow null values.
Deepak - JOT Servlets provides an Iterator bean that wraps a JDBC
ResultSet for repeating rows of output on a web page. You can
work directly with the ResultSet methods instead of transferring the
values to another Collection like a Vector.
-- Paul Copeland, JOT Object Technologies - http://www.jotobjects.com
------------------------------
Date: Tue, 19 Nov 2002 03:50:31 -0600
From: Amit Wadhwa <[EMAIL PROTECTED]>
Subject: Re: Use of Vectors in JSP
i use a 2-dimensional array.
i have a bean to which i send the query,
the query is processed by the bean, stored in an 2-d array, and the
array is stored as an object in a hashtable which is returned to the
calling jsp/servlet where i iterate thru the 2-d array and get the
results.
its working pretty ok but u have tro b careful about null pointer
exceptions.
anyone with any suggestions on this?
*****************************************
Amit Wadhwa
Technical Support Representative,
Dell International Services,
Bangalore
*****************************************
-----Original Message-----
From: Hans Bergsten [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, November 19, 2002 10:47 AM
To: [EMAIL PROTECTED]
Subject: Re: Use of Vectors in JSP
Deepak wrote:
Hi all
Would you recommend the use of Vectors in jsp pages to hold the query
results
from a database?
Is it ok then performance wise to iterate over the vector and display
the
items in the jsp page?
For example, a method in a javabean executes a jdbc statement that
returns
some recordsets. These recordsets are added to a Vector and the Vector
is
returned by the method.
In my jsp page I get the Vector with recordsets from the bean method.
Then I iterate over the Vector to display its items in a html table.
Is this a good way of doing things?
If not can anyone suggest a better way?
The methods in Vector are synchronized, so a List or an array is a
slightly more efficient approach. But I would suggest that you look at
JSTL instead. It's <sql:query> action exposes the query result as a
type called a Result. From a Result, you can get an array of arrays
where the first dimension represents rows and the second the column
value, or as an array of Maps where each Map represents a row, with
keys matching column names. Even if you access the database in servlet
code (for instance), you can use utility methods to convert a JDBC
ResultSet to a JSTL Result.
For more info, see:
<http://java.sun.com/products/jsp/jstl/>
Hans
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