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Techniques for form editing
A tag library such as the one that comes with the
Blazix server,
may not be available in your environment. How can you allow similar
features without using a tag library?
It is a little tedious, but it can be done. Basically, you must edit
each HTML tag yourself, and put in a default value. The following
examples shows how we modify GetName.jsp to provide features similar to blx:getProperty
but with manual HTML tag editing:
<jsp:useBean id="user" class="UserData" scope="session"/>
<HTML>
<BODY>
<FORM METHOD=POST ACTION="SaveName.jsp">
What's your name? <INPUT TYPE=TEXT NAME=username
SIZE=20 VALUE="<%= user.getUsername() %>"><BR>
What's your e-mail address? <INPUT TYPE=TEXT
NAME=email SIZE=20
VALUE="<%= user.getEmail() %>"><BR>
What's your age? <INPUT TYPE=TEXT NAME=age
SIZE=4 VALUE=<%= user.getAge() %>>
<P><INPUT TYPE=SUBMIT>
</FORM>
</BODY>
</HTML>
As you can see, this simply involves adding a "VALUE" field in the INPUT tags,
and initializing the field with an expression!
To handle exceptions during input processing, a simple approach is to use "String"
fields in the bean, and do the conversion to the target datatype
yourself. This will allow you to handle exceptions.
Exercise: Modify the earlier example to do everything without the
Blazix tag library (you can restrict this to only one field.) |