Validating Complex Input Without a Bean
look at the two remaining database
sections, let’s go back and take a look at the two
application pages we skipped earlier, namely the
pages used for input to the employee registration.
In Chapter 8, I introduced you to validation of
user input using the JSTL
<c:if> action as
well as using an application-specific bean. The bean contains all
validation code and can therefore validate the format of complex
data, such as date strings, email addresses, and credit-card numbers.
This is the approach I recommend, but if you’re
developing a JSP-based application without access to a Java
programmer to develop the beans you need, I’ll show
you a trick you can use to validate dates and a custom action for
validate.jsp page uses the JSTL
<c:if> action and the custom actions to
validate all user input. If an input parameter isn’t
valid, an error message is saved in a variable, and the request is
forwarded back to the
enter.jsp page. The
enter.jsp page adds all the error messages to
the response, so to the user, the result is identical to the
bean-based validation approach you saw in Chapter 8.
Let’s look at
shown in Example 11-8.
Example 11-8. Validation with application beans (validate.jsp)
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %> <%@ taglib prefix="fmt" uri="http://java.sun.com/jstl/fmt" %> <%@ taglib prefix="ora" uri="orataglib" %> <c:set var="isValid" ...