Java Reference
In-Depth Information
After entering the resource name for our datasource, saving, then clicking on
OK
, we
can see it listed in the
Resource References
section of our application's
web.xml
.
At this point we are ready to use the JSTL SQL library.
Retrieving database data with the <sql:query>
tag
The first JSTL SQL tag that we will cover is the
<sql:query>
tag. This tag allows us
to execute an SQL SELECT statement, and store it in an object implementing the
javax.servlet.jsp.jstl.sql.Result
interface. We can then iterate through this
object with the standard JSTL
<c:forEach>
tag.
The
javax.servlet.jsp.jstl.sql.Result
interface defines a number of methods
that we can call from a
<c:forEach>
tag in order to display database data on the
page. These methods are outlined in the following table:
Method Name
Description
getColumnNames()
Returns an array of
String
objects containing the column
names in the result set.
getRowCount()
Returns an
int
indicating the number of rows in the result
set.
getRows()
Returns an array of
java.util.SortedMap
objects. Each
element in the array represents a row in the result set. Keys in
each
SortedMap
are
String
objects containing the column
names, values are objects representing the value for the
column in the current row.
