Infact, I don’t think that there are any implicit methods in JSP but I know there are 9 implicit objects. The methods of these 9 implicit objects and classes readily available for the Programmer, I call them, as JSP implicit methods. I concentrate especially on 4 interfaces because the methods of these interfaces are useful to communicate data in between all JSPs of a Web application.
The importance of these 4 JSP Implicit Methods of request, session, application and pageContext is that they can transfer information between JSP pages and Servlets as an easy data-sharing mechanism. The standard methods provided by these objects are very helpful to set and get the values.
Following is the table of 4 JSP Implicit Methods for storing and retrieving attribute values.
|setAttribute(String key, Object value)||Known as set attribute which associates a value with a key. Returns void.|
|getAttributeNames()||Returns the keys of all attributes set with session object. Returns an object of Enumeration.|
|getAttribute(String key)||Known as get attribute which returns the value associated with the key. Returns an object of Object class.|
|removeAttribute(String key)||Removes the attribute value set with the key earlier. Returns void.|
The set attribute methods take data as key/value pairs where key is java.lang.String object and value is an object of java.lang.Object.