[Jsp] JSP API

JSP API

- javax.servlet.jsp

- javax.servlet.jsp.tagext

1. javax.servlet.jsp

The javax.servlet.jsp package has two interface and classes

- JspPage

- HttpJspPage

1_1. JspPage interface

- All the generated servlet classes must implement the JspPage interface

- It extends the Servlet interface, It provides two life cycle methods

* Mehtods of JspPage interface

1) public void jspInit()

- It is invoked only once during the life cycle of the JSP when JSP page is requested firstly.

- It is used to perform initializationi. It is same as the init() method of Servlet

2) public void jspDestroy()

- It is invoked only once during the life cycle of the JSP before the JSP page is destroyed

1_2. The HttpJspPage interface

- The HttpJspPage interface provides the one life cycle method of JSP.

- It extends the JspPage interface

* Method of HttpJspPage interface

1) public void _jspService()

- It is invoked each time when request for the JSP page comes to the container.

- It is used to process the request. 

- The underscore _ signifies that you cannot override this method