scriptlet Tag

`scriptlet` Tag

The scriptlet tag is the most important tag in the JSP specification since it enables the actual embedding of Java code within an HTML page. The Java code within the scriptlet tag is put by the JSP parser in the service() method of the resultant servlet generated.

Structure of the `scriptlet` Tag

The structure of the scriptlet tag is as follows:

 <%  // write all the Java statements %>

 <jsp:scriptlet>  // java code </jsp:scriptlet>

The Java code within the scriptlet tag is placed in the service() method of the servlet generated from the JSP. Any HTML code before or after these tags is converted into out.println(...) statements.

This example represents the true power of JSP tags:

 <BODY>  <!--list the names of the books in the shop --> <% for(int i=0; i < bookVector.size(); i++) {      out.println((String)bookVector.elementAt(i)); } %>

 <BODY>  <!--list the names of the books in the shop --> <jsp:scriptlet> for(int i=0; i < bookVector.size(); i++) {      out.println((String)bookVector.elementAt(i)); } </jsp:scriptlet>

As you can see, there is a Vector of book names named bookVector. You will be printing the contents of the bookVector on the browser. The entire Java code is put within the scriptlet tags. This Java code will be put in the service() method of the JSP's servlet. Note that the following statement used a new technique to print the output in the browser:

 out.println((String)bookVector.elementAt(i));

The out variable is the PrintWriter stream of the HttpResponse object that can be used to send data to the browser. The out variable is called an implicit variable in JSP. You will be studying implicit variables in the section "Implicit Variables" later today.

scriptlet Tag

Structure of the scriptlet Tag

`scriptlet` Tag

Structure of the `scriptlet` Tag