Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.
13.3 Setting Bean Properties
299
Associating Individual Properties with Input 
Parameters
Setting the 
itemID
 property was easy since its value is a 
String
. Setting the
numItems
 and 
discountCode
 properties is a bit more problematic since
their values must be numbers and 
getParameter
 returns a 
String
. Here is
the somewhat cumbersome code required to set 
numItems
:
<%
int numItemsOrdered = 1;
try {
  numItemsOrdered = 
    Integer.parseInt(request.getParameter("numItems"));
} catch(NumberFormatException nfe) {}
%>
    name="entry" 
    property="numItems"
    value="<%= numItemsOrdered %>" />
Fortunately, JSP has a nice solution to this problem that lets you associate
a property with a request parameter and that automatically performs type
conversion from strings to numbers, characters, and boolean values. Instead
of using the 
value
 attribute, you use 
param
 to name an input parameter. The
value of this parameter is automatically used as the value of the property, and
simple type conversions are performed automatically. If the specified input
parameter is missing from the request, no action is taken (the system does
not pass 
null
 to the associated property). So, for example, setting the
numItems
 property can be simplified to:
Figure 13 2 Result of SaleEntry1.jsp.
Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com.
Servlet and JSP training courses by book's author: courses.coreservlets.com.






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