Action: Follows the XML (eXtended Markup Language) format and always begins with <jsp:some action/>. It provides a way to add more functionality to JSP, such as finding or instantiating (creating) a JavaBean for use later. You see one example of an action tag in line 12 of the code in Listing 1-1.
Directive: A message to the Web container describing page properties, specifying tag libraries, or substituting text or code at translation time. The form is <%@ the directive %>. Listing 1-1 has directives on lines 1, 3, and 5.
Declaration: Declares one or more Java variables or methods that you can use later in your page. The tag has this form <%! declaration %>.
Expression: Defines a Java expression that is evaluated to a String. Its form is <%= expression %>.
Scriptlet: Inserts Java code into the page to perform some function not available with the other tag elements. Its form is <% java code %>.
Comment: A brief explanation of a line or lines of code by the developer. Comments have the form <%– the comment –%>. Lines 2 and 4 in Listing 1-1 are examples of comments.
Listing 1-1 Sample JSP Page 1 <%@ page contentType=”text/html;charset=UTF- 8”language=”java” %> 2 <%– JSTL tag libs –%> 3 <%@ taglib prefix=”fmt” uri=”/WEB-INF/fmt.tld” %> 4 <%– Struts provided Taglibs –%> 5 <%@ taglib uri=”/WEB-INF/struts-html-el.tld” prefix=”html” %> 6 <html:html locale=”true”/> 7 <head> 8 <fmt:setBundle basename=”ApplicationResources” /> 9 <title><fmt:message key=”loggedin.title”/></title> 10 </head> 11 <body> 12 <jsp:useBean id=”polBean” class=”com.othenos.purchasing.struts.POListBean”/> 13 <H2> 14 <fmt:message key=”loggedin.msg”> 15 <fmt:param value=’${polBean.userName}’ /> 16 </fmt:message> 17 </H2> 18 </body> 19 </html>