Creates a cookie, a small amount of information sent by a servlet to
a Web browser, saved by the browser, and later sent back to the server.
A cookie's value can uniquely
identify a client, so cookies are commonly used for session management.
A cookie has a name, a single value, and optional attributes
such as a comment, path and domain qualifiers, a maximum age, and a
version number. Some Web browsers have bugs in how they handle the
optional attributes, so use them sparingly to improve the interoperability
of your servlets.
The servlet sends cookies to the browser by using the
HttpServletResponse.addCookie(Cookie) method, which adds
fields to HTTP response headers to send cookies to the
browser, one at a time. The browser is expected to
support 20 cookies for each Web server, 300 cookies total, and
may limit cookie size to 4 KB each.
The browser returns cookies to the servlet by adding
fields to HTTP request headers. Cookies can be retrieved
from a request by using the
HttpServletRequest.getCookies() method.
Several cookies might have the same name but different path attributes.
Cookies affect the caching of the Web pages that use them.
HTTP 1.0 does not cache pages that use cookies created with
this class. This class does not support the cache control
defined with HTTP 1.1.
This class supports both the Version 0 (by Netscape) and Version 1
(by RFC 2109) cookie specifications. By default, cookies are
created using Version 0 to ensure the best interoperability.
clone
public java.lang.Object clone()
Overrides the standard java.lang.Object.clone
method to return a copy of this cookie.
getComment
public java.lang.String getComment()
Returns the comment describing the purpose of this cookie, or
null if the cookie has no comment.
- a
String containing the comment,
or null if none
setComment(java.lang.String)
getDomain
public java.lang.String getDomain()
Returns the domain name set for this cookie. The form of
the domain name is set by RFC 2109.
- a
String containing the domain name
setDomain(java.lang.String)
getMaxAge
public int getMaxAge()
Returns the maximum age of the cookie, specified in seconds,
By default, -1 indicating the cookie will persist
until browser shutdown.
- an integer specifying the maximum age of the
cookie in seconds; if negative, means
the cookie persists until browser shutdown
setMaxAge(int)
getName
public java.lang.String getName()
Returns the name of the cookie. The name cannot be changed after
creation.
- a
String specifying the cookie's name
getPath
public java.lang.String getPath()
Returns the path on the server
to which the browser returns this cookie. The
cookie is visible to all subpaths on the server.
- a
String specifying a path that contains
a servlet name, for example, /catalog
setPath(java.lang.String)
getSecure
public boolean getSecure()
Returns true if the browser is sending cookies
only over a secure protocol, or false if the
browser can send cookies using any protocol.
true if the browser uses a secure protocol;
otherwise, true
setSecure(boolean)
getVersion
public int getVersion()
Returns the version of the protocol this cookie complies
with. Version 1 complies with RFC 2109,
and version 0 complies with the original
cookie specification drafted by Netscape. Cookies provided
by a browser use and identify the browser's cookie version.
- 0 if the cookie complies with the
original Netscape specification; 1
if the cookie complies with RFC 2109
setVersion(int)
setComment
public void setComment(java.lang.String purpose)
Specifies a comment that describes a cookie's purpose.
The comment is useful if the browser presents the cookie
to the user. Comments
are not supported by Netscape Version 0 cookies.
purpose - a String specifying the comment
to display to the user
getComment()
setDomain
public void setDomain(java.lang.String pattern)
Specifies the domain within which this cookie should be presented.
The form of the domain name is specified by RFC 2109. A domain
name begins with a dot (
.foo.com) and means that
the cookie is visible to servers in a specified Domain Name System
(DNS) zone (for example,
www.foo.com, but not
a.b.foo.com). By default, cookies are only returned
to the server that sent them.
pattern - a String containing the domain name
within which this cookie is visible;
form is according to RFC 2109
getDomain()
setMaxAge
public void setMaxAge(int expiry)
Sets the maximum age of the cookie in seconds.
A positive value indicates that the cookie will expire
after that many seconds have passed. Note that the value is
the
maximum age when the cookie will expire, not the cookie's
current age.
A negative value means
that the cookie is not stored persistently and will be deleted
when the Web browser exits. A zero value causes the cookie
to be deleted.
expiry - an integer specifying the maximum age of the
cookie in seconds; if negative, means
the cookie is not stored; if zero, deletes
the cookie
getMaxAge()
setPath
public void setPath(java.lang.String uri)
Specifies a path for the cookie
to which the client should return the cookie.
The cookie is visible to all the pages in the directory
you specify, and all the pages in that directory's subdirectories.
A cookie's path must include the servlet that set the cookie,
for example,
/catalog, which makes the cookie
visible to all directories on the server under
/catalog.
Consult RFC 2109 (available on the Internet) for more
information on setting path names for cookies.
uri - a String specifying a path
getPath()
setSecure
public void setSecure(boolean flag)
Indicates to the browser whether the cookie should only be sent
using a secure protocol, such as HTTPS or SSL.
The default value is
false.
flag - if true, sends the cookie from the browser
to the server using only when using a secure protocol;
if false, sent on any protocol
getSecure()
setValue
public void setValue(java.lang.String newValue)
Assigns a new value to a cookie after the cookie is created.
If you use a binary value, you may want to use BASE64 encoding.
With Version 0 cookies, values should not contain white
space, brackets, parentheses, equals signs, commas,
double quotes, slashes, question marks, at signs, colons,
and semicolons. Empty values may not behave the same way
on all browsers.
newValue - a String specifying the new value
getValue(), Cookie
setVersion
public void setVersion(int v)
Sets the version of the cookie protocol this cookie complies
with. Version 0 complies with the original Netscape cookie
specification. Version 1 complies with RFC 2109.
Since RFC 2109 is still somewhat new, consider
version 1 as experimental; do not use it yet on production sites.
v - 0 if the cookie should comply with
the original Netscape specification;
1 if the cookie should comply with RFC 2109
getVersion()