public interface HttpSession
The servlet container uses this interface to create a session between an HTTP client and an HTTP server. The session persists for a specified time period, across more than one connection or page request from the user. A session usually corresponds to one user, who may visit a site many times. The server can maintain a session in many ways such as using cookies or rewriting URLs.
This interface allows servlets to
When an application stores an object in or removes an object from a
session, the session checks whether the object implements
HttpSessionBindingListener
. If it does,
the servlet notifies the object that it has been bound to or unbound
from the session. Notifications are sent after the binding methods complete.
For session that are invalidated or expire, notifications are sent after
the session has been invalidated or expired.
When container migrates a session between VMs in a distributed container
setting, all session attributes implementing the HttpSessionActivationListener
interface are notified.
A servlet should be able to handle cases in which
the client does not choose to join a session, such as when cookies are
intentionally turned off. Until the client joins the session,
isNew
returns true
. If the client chooses
not to join
the session, getSession
will return a different session
on each request, and isNew
will always return
true
.
Session information is scoped only to the current web application
(ServletContext
), so information stored in one context
will not be directly visible in another.
HttpSessionBindingListener
,
HttpSessionContext
Modifier and Type | Method and Description |
---|---|
Object |
getAttribute(String name)
Returns the object bound with the specified name in this session, or
null if no object is bound under the name. |
Enumeration<String> |
getAttributeNames()
Returns an
Enumeration of String objects
containing the names of all the objects bound to this session. |
long |
getCreationTime()
Returns the time when this session was created, measured
in milliseconds since midnight January 1, 1970 GMT.
|
String |
getId()
Returns a string containing the unique identifier assigned
to this session.
|
long |
getLastAccessedTime()
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.
|
int |
getMaxInactiveInterval()
Returns the maximum time interval, in seconds, that
the servlet container will keep this session open between
client accesses.
|
ServletContext |
getServletContext()
Returns the ServletContext to which this session belongs.
|
HttpSessionContext |
getSessionContext()
Deprecated.
As of Version 2.1, this method is
deprecated and has no replacement.
It will be removed in a future
version of the Java Servlet API.
|
Object |
getValue(String name)
Deprecated.
As of Version 2.2, this method is
replaced by
getAttribute(java.lang.String) . |
String[] |
getValueNames()
Deprecated.
As of Version 2.2, this method is
replaced by
getAttributeNames() |
void |
invalidate()
Invalidates this session then unbinds any objects bound
to it.
|
boolean |
isNew()
Returns
true if the client does not yet know about the
session or if the client chooses not to join the session. |
void |
putValue(String name,
Object value)
Deprecated.
As of Version 2.2, this method is
replaced by
setAttribute(java.lang.String, java.lang.Object) |
void |
removeAttribute(String name)
Removes the object bound with the specified name from
this session.
|
void |
removeValue(String name)
Deprecated.
As of Version 2.2, this method is
replaced by
removeAttribute(java.lang.String) |
void |
setAttribute(String name,
Object value)
Binds an object to this session, using the name specified.
|
void |
setMaxInactiveInterval(int interval)
Specifies the time, in seconds, between client requests before the
servlet container will invalidate this session.
|
long getCreationTime()
long
specifying
when this session was created,
expressed in
milliseconds since 1/1/1970 GMTIllegalStateException
- if this method is called on an
invalidated sessionString getId()
long getLastAccessedTime()
Actions that your application takes, such as getting or setting a value associated with the session, do not affect the access time.
long
representing the last time
the client sent a request associated
with this session, expressed in
milliseconds since 1/1/1970 GMTIllegalStateException
- if this method is called on an
invalidated sessionServletContext getServletContext()
void setMaxInactiveInterval(int interval)
An interval value of zero or less indicates that the session should never timeout.
interval
- An integer specifying the number
of secondsint getMaxInactiveInterval()
setMaxInactiveInterval
method.
A return value of zero or less indicates that the session will never timeout.
setMaxInactiveInterval(int)
HttpSessionContext getSessionContext()
Object getAttribute(String name)
null
if no object is bound under the name.name
- a string specifying the name of the objectIllegalStateException
- if this method is called on an
invalidated sessionObject getValue(String name)
getAttribute(java.lang.String)
.name
- a string specifying the name of the objectIllegalStateException
- if this method is called on an
invalidated sessionEnumeration<String> getAttributeNames()
Enumeration
of String
objects
containing the names of all the objects bound to this session.Enumeration
of
String
objects specifying the
names of all the objects bound to
this sessionIllegalStateException
- if this method is called on an
invalidated sessionString[] getValueNames()
getAttributeNames()
String
objects specifying the
names of all the objects bound to
this sessionIllegalStateException
- if this method is called on an
invalidated sessionvoid setAttribute(String name, Object value)
After this method executes, and if the new object
implements HttpSessionBindingListener
,
the container calls
HttpSessionBindingListener.valueBound
. The container then
notifies any HttpSessionAttributeListener
s in the web
application.
If an object was already bound to this session of this name
that implements HttpSessionBindingListener
, its
HttpSessionBindingListener.valueUnbound
method is called.
If the value passed in is null, this has the same effect as calling
removeAttribute()
.
name
- the name to which the object is bound;
cannot be nullvalue
- the object to be boundIllegalStateException
- if this method is called on an
invalidated sessionvoid putValue(String name, Object value)
setAttribute(java.lang.String, java.lang.Object)
name
- the name to which the object is bound;
cannot be nullvalue
- the object to be bound; cannot be nullIllegalStateException
- if this method is called on an
invalidated sessionvoid removeAttribute(String name)
After this method executes, and if the object
implements HttpSessionBindingListener
,
the container calls
HttpSessionBindingListener.valueUnbound
. The container
then notifies any HttpSessionAttributeListener
s in the web
application.
name
- the name of the object to
remove from this sessionIllegalStateException
- if this method is called on an
invalidated sessionvoid removeValue(String name)
removeAttribute(java.lang.String)
name
- the name of the object to
remove from this sessionIllegalStateException
- if this method is called on an
invalidated sessionvoid invalidate()
IllegalStateException
- if this method is called on an
already invalidated sessionboolean isNew()
true
if the client does not yet know about the
session or if the client chooses not to join the session. For
example, if the server used only cookie-based sessions, and
the client had disabled the use of cookies, then a session would
be new on each request.true
if the
server has created a session,
but the client has not yet joinedIllegalStateException
- if this method is called on an
already invalidated sessionCopyright © 2018 JBoss by Red Hat. All rights reserved.