Use the Connection Pooling feature available in JDBC.
Remarks
Connection pooling is a mechanism whereby when an application
closes a connection, that connection is recycled rather than being destroyed.
Because establishing a connection is an expensive operation, reusing connections
can improve performance dramatically by reducing the number of new connections
that need to be created. Connection pooling is especially useful in Middle Tier
layers.
To demonstrate this feature, this example implements ConnectionPoolingBean,
called from JSPs in a middle tier. The JSPs render the UI, and invoke the JavaBean
to reserve and canel hotel rooms.
Also, this example uses the JML
tags available with OC4J JSP. Many of the JML tags are intended to simplify
coding syntax for JSP developers who are not proficient with Java. This example
uses JML tags to execute certain code blocks only when certain conditions are
met.
Code from CancelBookings.jsp
<jml:setProperty name="connPool" property="hotelId" value="<%= request.getParameter(\"HOTEL_ID\") %>" /> <jml:setProperty name="connPool" property="reqType" value="<%= request.getParameter(\"REQ_TYPE\") %>" /> <jml:choose> <jml:when condition =
"<%= connPool.getReqType().toUpperCase().equals(\"CANCEL_FORM\") %>" > <%-- If the value of the parameter REQ_TYPE is "CANCEL_FORM" then, display the existing bookings for the user to select one and submit. --%> <FORM onSubmit="return validatecancel()"> <CENTER> <%= connPool.getBookings() %> <INPUT type=button value="Close" onClick="window.close();"> <INPUT type=hidden name="HOTEL_ID" value=<%=connPool.getHotelId()%>> <INPUT type=hidden name="REQ_TYPE" value=""> <INPUT type=hidden name="BOOKING_ID" value=""> </CENTER> </FORM> </jml:when> <jml:when condition =
"<%= connPool.getReqType().toUpperCase().equals(\"DO_CANCEL\") %>" > <%-- If the value of the parameter REQ_TYPE is "DO_CANCEL" then, call the bean
method to delete the booking from the database. --%> <FORM> <BR> <% String l_bookingId = request.getParameter("BOOKING_ID"); %> <%= connPool.cancel(l_bookingId) %> <BR> <CENTER> <INPUT type=SUBMIT value="Back"> <INPUT type=button value="Close" onClick="window.close();"> <INPUT type=hidden name="REQ_TYPE" value="CANCEL_FORM"> <INPUT type=hidden name="HOTEL_ID" value=<%=connPool.getHotelId()%> > <INPUT type=hidden name="BOOKING_ID" value=""> </CENTER> </FORM> </jml:when> </jml:choose>
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