Top Description Fields Constructors Methods
javax.servlet.http

public Class Cookie

extends Object
implements Cloneable
Class Inheritance
All Implemented Interfaces
java.lang.Cloneable
Imports
java.text.MessageFormat, java.util.ResourceBundle
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 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.

Version
$Rev: 46019 $ $Date: 2004-09-14 04:56:06 -0500 (Tue, 14 Sep 2004) $

Field Summary

Modifier and TypeField and Description
private String
comment

private String
domain

private static final String
LSTRING_FILE

private static ResourceBundle
lStrings

private int
maxAge

private String
name

private String
path

private boolean
secure

private static final String
tspecials

private String
value

private int
version

Constructor Summary

AccessConstructor and Description

Method Summary

Modifier and TypeMethod and Description
public Object
clone()

Overrides java.lang.Object.clone.

Overrides the standard java.lang.Object.clone method to return a copy of this cookie.
public String

Returns:

a String containing the comment, or null if none
getComment()

Returns the comment describing the purpose of this cookie, or null if the cookie has no comment.

public String

Returns:

a String containing the domain name
getDomain()

Returns the domain name set for this cookie.

public int

Returns:

an integer specifying the maximum age of the cookie in seconds; if negative, means the cookie persists until browser shutdown
getMaxAge()

Returns the maximum age of the cookie, specified in seconds, By default, -1 indicating the cookie will persist until browser shutdown.

public String

Returns:

a String specifying the cookie's name
getName()

Returns the name of the cookie.

public String

Returns:

a String specifying a path that contains a servlet name, for example, /catalog
getPath()

Returns the path on the server to which the browser returns this cookie.

public boolean

Returns:

true if the browser uses a secure protocol; otherwise, true
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.

public String

Returns:

a String containing the cookie's present value
getValue()

Returns the value of the cookie.

public int

Returns:

0 if the cookie complies with the original Netscape specification; 1 if the cookie complies with RFC 2109
getVersion()

Returns the version of the protocol this cookie complies with.

private boolean

Returns:

true if the String is a reserved token; false if it is not
isToken(String
the String to be tested
value)

Tests a string and returns true if the string counts as a reserved token in the Java language.

public void
setComment(String
a String specifying the comment to display to the user
purpose)

Specifies a comment that describes a cookie's purpose.

public void
setDomain(String
a String containing the domain name within which this cookie is visible; form is according to RFC 2109
pattern)

Specifies the domain within which this cookie should be presented.

public void
setMaxAge(int
an integer specifying the maximum age of the cookie in seconds; if negative, means the cookie is not stored; if zero, deletes the cookie
expiry)

Sets the maximum age of the cookie in seconds.

public void
setPath(String
a String specifying a path
uri)

Specifies a path for the cookie to which the client should return the cookie.

public void
setSecure(boolean
if true, sends the cookie from the browser to the server only when using a secure protocol; if false, sent on any protocol
flag)

Indicates to the browser whether the cookie should only be sent using a secure protocol, such as HTTPS or SSL.

public void
setValue(String
a String specifying the new value
newValue)

Assigns a new value to a cookie after the cookie is created.

public void
setVersion(int
0 if the cookie should comply with the original Netscape specification; 1 if the cookie should comply with RFC 2109
v)

Sets the version of the cookie protocol this cookie complies with.

Inherited from java.lang.Object:
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Field Detail

commentback to summary
private String comment
domainback to summary
private String domain
LSTRING_FILEback to summary
private static final String LSTRING_FILE
lStringsback to summary
private static ResourceBundle lStrings
maxAgeback to summary
private int maxAge
nameback to summary
private String name
pathback to summary
private String path
secureback to summary
private boolean secure
tspecialsback to summary
private static final String tspecials
valueback to summary
private String value
versionback to summary
private int version

Constructor Detail

Cookieback to summary
public Cookie(String name, String value)

Constructs a cookie with a specified name and value.

The name must conform to RFC 2109. That means it can contain only ASCII alphanumeric characters and cannot contain commas, semicolons, or white space or begin with a $ character. The cookie's name cannot be changed after creation.

The value can be anything the server chooses to send. Its value is probably of interest only to the server. The cookie's value can be changed after creation with the setValue method.

By default, cookies are created according to the Netscape cookie specification. The version can be changed with the setVersion method.

Parameters
name:String

a String specifying the name of the cookie

value:String

a String specifying the value of the cookie

Exceptions
IllegalArgumentException:
if the cookie name contains illegal characters (for example, a comma, space, or semicolon) or it is one of the tokens reserved for use by the cookie protocol
See Also
setValue, setVersion

Method Detail

cloneback to summary
public Object clone()

Overrides java.lang.Object.clone.

Overrides the standard java.lang.Object.clone method to return a copy of this cookie.

Returns:Object

Doc from java.lang.Object.clone.

a clone of this instance.

getCommentback to summary
public String getComment()

Returns the comment describing the purpose of this cookie, or null if the cookie has no comment.

Returns:String

a String containing the comment, or null if none

See Also
setComment
getDomainback to summary
public String getDomain()

Returns the domain name set for this cookie. The form of the domain name is set by RFC 2109.

Returns:String

a String containing the domain name

See Also
setDomain
getMaxAgeback to summary
public int getMaxAge()

Returns the maximum age of the cookie, specified in seconds, By default, -1 indicating the cookie will persist until browser shutdown.

Returns:int

an integer specifying the maximum age of the cookie in seconds; if negative, means the cookie persists until browser shutdown

See Also
setMaxAge
getNameback to summary
public String getName()

Returns the name of the cookie. The name cannot be changed after creation.

Returns:String

a String specifying the cookie's name

getPathback to summary
public 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.

Returns:String

a String specifying a path that contains a servlet name, for example, /catalog

See Also
setPath
getSecureback to summary
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.

Returns:boolean

true if the browser uses a secure protocol; otherwise, true

See Also
setSecure
getValueback to summary
public String getValue()

Returns the value of the cookie.

Returns:String

a String containing the cookie's present value

See Also
setValue, Cookie
getVersionback to summary
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.

Returns:int

0 if the cookie complies with the original Netscape specification; 1 if the cookie complies with RFC 2109

See Also
setVersion
isTokenback to summary
private boolean isToken(String value)

Tests a string and returns true if the string counts as a reserved token in the Java language.

Parameters
value:String

the String to be tested

Returns:boolean

true if the String is a reserved token; false if it is not

setCommentback to summary
public void setComment(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.

Parameters
purpose:String

a String specifying the comment to display to the user

See Also
getComment
setDomainback to summary
public void setDomain(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.

Parameters
pattern:String

a String containing the domain name within which this cookie is visible; form is according to RFC 2109

See Also
getDomain
setMaxAgeback to summary
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.

Parameters
expiry:int

an integer specifying the maximum age of the cookie in seconds; if negative, means the cookie is not stored; if zero, deletes the cookie

See Also
getMaxAge
setPathback to summary
public void setPath(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.

Parameters
uri:String

a String specifying a path

See Also
getPath
setSecureback to summary
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.

Parameters
flag:boolean

if true, sends the cookie from the browser to the server only when using a secure protocol; if false, sent on any protocol

See Also
getSecure
setValueback to summary
public void setValue(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.

Parameters
newValue:String

a String specifying the new value

See Also
getValue, Cookie
setVersionback to summary
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.

Parameters
v:int

0 if the cookie should comply with the original Netscape specification; 1 if the cookie should comply with RFC 2109

See Also
getVersion