JSP Tutorial

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.)

Conclusion: Material for further learning

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