J2EE™ Tutorial, The

Extending the JSP Language

You can perform a wide variety of dynamic processing tasks including accessing databases, using enterprise services such as e-mail and directories, and managing flow control with JavaBeans components in conjunction with scriptlets. One of the drawbacks of scriptlets, however, is that they tend to make JSP pages more difficult to maintain. Alternatively, JSP technology provides a mechanism, called custom tags, that allows you to encapsulate dynamic functionality in objects that are accessed through extensions to the JSP language. Custom tags bring the benefits of another level of componentization to JSP pages.

For example, recall the scriptlet used to loop through and display the contents of the Duke’s Bookstore shopping ...