Prentice.Hall.Introduction.to.Java.Programming,.Brief.Version.9th.(2014).[sharethefiles.com]

«interface»
javax.servlet.http.HttpSession
+getAttribute(name: String): Object
+setAttribute(name: String, value: Object):
void
+getId(): String
+getLastAccessedTime(): long
+invalidate(): void
+isNew(): boolean
+removeAttribute(name: String): void
+getMaxInactiveInterval(): int
+setMaxInactiveInterval(interval: int): void
Figure 42.24
Returns the object bound with the specified name in this session, or null if no
object is bound under the name.
Binds an object to this session, using the specified name. If an object of the
same name is already bound to the session, the object is replaced.
Returns a string containing the unique identifier assigned to this session. The
identifier is assigned by the servlet container and is implementation
dependent.
Returns the last time the client sent a request associated with this session, as the
number of milliseconds since midnight January 1, 1970 GMT, and marked by
the time the container received the request.
Invalidates this session, then unbinds any objects bound to it.
Returns true if the session was just created in the current request.
Removes the object bound with the specified name from this session. If the
session does not have an object bound with the specified name, this method does
nothing.
Returns the time, in seconds, between client requests before the servlet container
will invalidate this session. A negative time indicates that the session will
never time-out. Use setMaxInactiveInterval to specify this value.
HttpSession establishes a persistent session between a client with
multiple requests and the server.
NOTE: HTTP is stateless. So how does the server associate
a session with multiple requests from the same client?
This is handled behind the scenes by the servlet
container and is transparent to the servlet programmer.
To demonstrate using HttpSession, let us rewrite Listing 42.9,
Registration.java, and Listing 42.10, RegistrationWithCookie.java.
Instead of using hidden values or cookies for session tracking, it uses
servlet HttpSession.
Create the servlet named RegistrationWithHttpSession in Listing 42.11.
Create an HTML file named RegistrationWithHttpSession.html that is
identical to Registration.html except that the action is replaced by
RegistrationWithHttpSessionH.
Listing 42.11 RegistrationWithHttpSession.java
package chapter42;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;
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