HttpCookie (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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java.net
Class HttpCookie

java.lang.Object
  java.net.HttpCookie

All Implemented Interfaces:: Cloneable

public final class HttpCookie
extends Object
implements Cloneable
extends Object
implements Cloneable

An HttpCookie object represents an http cookie, which carries state information between server and user agent. Cookie is widely adopted to create stateful sessions.

There are 3 http cookie specifications:

Netscape draft
RFC 2109 - http://www.ietf.org/rfc/rfc2109.txt
RFC 2965 - http://www.ietf.org/rfc/rfc2965.txt

HttpCookie class can accept all these 3 forms of syntax.

Since:: 1.6

Constructor Summary

HttpCookie(String name, String value)
          Constructs a cookie with a specified name and value.

Method Summary

Object clone()
          Create and return a copy of this object.

static boolean domainMatches(String domain, String host)
          The utility method to check whether a host name is in a domain or not.

boolean equals(Object obj)
          Test the equality of two http cookies.

String getComment()
          Returns the comment describing the purpose of this cookie, or null if the cookie has no comment.

String getCommentURL()
          Returns the comment url describing the purpose of this cookie, or null if the cookie has no comment url.

boolean getDiscard()
          Return the discard attribute of the cookie

String getDomain()
          Returns the domain name set for this cookie.

long getMaxAge()
          Returns the maximum age of the cookie, specified in seconds.

String getName()
          Returns the name of the cookie.

String getPath()
          Returns the path on the server to which the browser returns this cookie.

String getPortlist()
          Return the port list attribute of the cookie

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.

String getValue()
          Returns the value of the cookie.

int getVersion()
          Returns the version of the protocol this cookie complies with.

boolean hasExpired()
          Reports whether this http cookie has expired or not.

int hashCode()
          Return hash code of this http cookie.

static List<HttpCookie> parse(String header)
          Constructs cookies from set-cookie or set-cookie2 header string.

void setComment(String purpose)
          Specifies a comment that describes a cookie's purpose.

void setCommentURL(String purpose)
          Specifies a comment url that describes a cookie's purpose.

void setDiscard(boolean discard)
          Specify whether user agent should discard the cookie unconditionally.

void setDomain(String pattern)
          Specifies the domain within which this cookie should be presented.

void setMaxAge(long expiry)
          Sets the maximum age of the cookie in seconds.

void setPath(String uri)
          Specifies a path for the cookie to which the client should return the cookie.

void setPortlist(String ports)
          Specify the portlist of the cookie, which restricts the port(s) to which a cookie may be sent back in a Cookie header.

void setSecure(boolean flag)
          Indicates to the browser whether the cookie should only be sent using a secure protocol, such as HTTPS or SSL.

void setValue(String newValue)
          Assigns a new value to a cookie after the cookie is created.

void setVersion(int v)
          Sets the version of the cookie protocol this cookie complies with.

String toString()
          Constructs a cookie header string representation of this cookie, which is in the format defined by corresponding cookie specification, but without the leading "Cookie:" token.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Summary
`HttpCookie(String name, String value)` Constructs a cookie with a specified name and value.

Method Summary
`Object`	`clone()` Create and return a copy of this object.
`static boolean`	`domainMatches(String domain, String host)` The utility method to check whether a host name is in a domain or not.
`boolean`	`equals(Object obj)` Test the equality of two http cookies.
`String`	`getComment()` Returns the comment describing the purpose of this cookie, or `null` if the cookie has no comment.
`String`	`getCommentURL()` Returns the comment url describing the purpose of this cookie, or `null` if the cookie has no comment url.
`boolean`	`getDiscard()` Return the discard attribute of the cookie
`String`	`getDomain()` Returns the domain name set for this cookie.
`long`	`getMaxAge()` Returns the maximum age of the cookie, specified in seconds.
`String`	`getName()` Returns the name of the cookie.
`String`	`getPath()` Returns the path on the server to which the browser returns this cookie.
`String`	`getPortlist()` Return the port list attribute of the cookie
`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.
`String`	`getValue()` Returns the value of the cookie.
`int`	`getVersion()` Returns the version of the protocol this cookie complies with.
`boolean`	`hasExpired()` Reports whether this http cookie has expired or not.
`int`	`hashCode()` Return hash code of this http cookie.
`static List<HttpCookie>`	`parse(String header)` Constructs cookies from set-cookie or set-cookie2 header string.
`void`	`setComment(String purpose)` Specifies a comment that describes a cookie's purpose.
`void`	`setCommentURL(String purpose)` Specifies a comment url that describes a cookie's purpose.
`void`	`setDiscard(boolean discard)` Specify whether user agent should discard the cookie unconditionally.
`void`	`setDomain(String pattern)` Specifies the domain within which this cookie should be presented.
`void`	`setMaxAge(long expiry)` Sets the maximum age of the cookie in seconds.
`void`	`setPath(String uri)` Specifies a path for the cookie to which the client should return the cookie.
`void`	`setPortlist(String ports)` Specify the portlist of the cookie, which restricts the port(s) to which a cookie may be sent back in a Cookie header.
`void`	`setSecure(boolean flag)` Indicates to the browser whether the cookie should only be sent using a secure protocol, such as HTTPS or SSL.
`void`	`setValue(String newValue)` Assigns a new value to a cookie after the cookie is created.
`void`	`setVersion(int v)` Sets the version of the cookie protocol this cookie complies with.
`String`	`toString()` Constructs a cookie header string representation of this cookie, which is in the format defined by corresponding cookie specification, but without the leading "Cookie:" token.

Methods inherited from class java.lang.Object
`finalize, getClass, notify, notifyAll, wait, wait, wait`

Constructor Detail

HttpCookie

public HttpCookie(String name,
                  String value)

Constructs a cookie with a specified name and value.

The name must conform to RFC 2965. 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 RFC 2965 cookie specification. The version can be changed with the setVersion method.

Parameters:: name - a String specifying the name of the cookie; value - a String specifying the value of the cookie
Throws:: IllegalArgumentException - if the cookie name contains illegal characters or it is one of the tokens reserved for use by the cookie protocol; NullPointerException - if name is null
See Also:: setValue(java.lang.String), setVersion(int)

Method Detail

parse

public static List<HttpCookie> parse(String header)

Constructs cookies from set-cookie or set-cookie2 header string. RFC 2965 section 3.2.2 set-cookie2 syntax indicates that one header line may contain more than one cookie definitions, so this is a static utility method instead of another constructor.

Parameters:: header - a String specifying the set-cookie header. The header should start with "set-cookie", or "set-cookie2" token; or it should have no leading token at all.
Returns:: a List of cookie parsed from header line string
Throws:: IllegalArgumentException - if header string violates the cookie specification's syntax, or the cookie name contains llegal characters, or the cookie name is one of the tokens reserved for use by the cookie protocol; NullPointerException - if the header string is null

hasExpired

public boolean hasExpired()

Reports whether this http cookie has expired or not.

Returns:: true to indicate this http cookie has expired; otherwise, false

setComment

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 - a String specifying the comment to display to the user
See Also:: getComment()

getComment

public String getComment()

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

Returns:: a String containing the comment, or null if none
See Also:: setComment(java.lang.String)

setCommentURL

public void setCommentURL(String purpose)

Specifies a comment url that describes a cookie's purpose. The comment url is useful if the browser presents the cookie to the user. Comment url is RFC 2965 only.

Parameters:: purpose - a String specifying the comment url to display to the user
See Also:: getCommentURL()

getCommentURL

public String getCommentURL()

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

Returns:: a String containing the comment url, or null if none
See Also:: setCommentURL(java.lang.String)

setDiscard

public void setDiscard(boolean discard)

Specify whether user agent should discard the cookie unconditionally. This is RFC 2965 only attribute.

Parameters:: discard - true indicates to discard cookie unconditionally
See Also:: getDiscard()

getDiscard

public boolean getDiscard()

Return the discard attribute of the cookie

Returns:: a boolean to represent this cookie's discard attribute
See Also:: setDiscard(boolean)

setPortlist

public void setPortlist(String ports)

Specify the portlist of the cookie, which restricts the port(s) to which a cookie may be sent back in a Cookie header.

Parameters:: ports - a String specify the port list, which is comma seperated series of digits
See Also:: getPortlist()

getPortlist

public String getPortlist()

Return the port list attribute of the cookie

Returns:: a String contains the port list or null if none
See Also:: setPortlist(java.lang.String)

setDomain

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 2965. 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 - a String containing the domain name within which this cookie is visible; form is according to RFC 2965
See Also:: getDomain()

getDomain

public String getDomain()

Returns the domain name set for this cookie. The form of the domain name is set by RFC 2965.

Returns:: a String containing the domain name
See Also:: setDomain(java.lang.String)

setMaxAge

public void setMaxAge(long 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 - an integer specifying the maximum age of the cookie in seconds; if zero, the cookie should be discarded immediately; otherwise, the cookie's max age is unspecified.
See Also:: getMaxAge()

getMaxAge

public long getMaxAge()

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

Returns:: an integer specifying the maximum age of the cookie in seconds
See Also:: setMaxAge(long)

setPath

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 2965 (available on the Internet) for more information on setting path names for cookies.

Parameters:: uri - a String specifying a path
See Also:: getPath()

getPath

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:: a String specifying a path that contains a servlet name, for example, /catalog
See Also:: setPath(java.lang.String)

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.

Parameters:: 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
See Also:: getSecure()

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.

Returns:: true if the browser can use any standard protocol; otherwise, false
See Also:: setSecure(boolean)

getName

public String getName()

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

Returns:: a String specifying the cookie's name

setValue

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 - a String specifying the new value
See Also:: getValue()

getValue

public String getValue()

Returns the value of the cookie.

Returns:: a String containing the cookie's present value
See Also:: setValue(java.lang.String)

getVersion

public int getVersion()

Returns the version of the protocol this cookie complies with. Version 1 complies with RFC 2965/2109, 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:: 0 if the cookie complies with the original Netscape specification; 1 if the cookie complies with RFC 2965/2109
See Also:: setVersion(int)

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 2965/2109.

Parameters:: v - 0 if the cookie should comply with the original Netscape specification; 1 if the cookie should comply with RFC 2965/2109
Throws:: IllegalArgumentException - if v is neither 0 nor 1
See Also:: getVersion()

domainMatches

public static boolean domainMatches(String domain,
                                    String host)

The utility method to check whether a host name is in a domain or not.

This concept is described in the cookie specification. To understand the concept, some terminologies need to be defined first:

effective host name = hostname if host name contains dot
or = hostname.local if not

Host A's name domain-matches host B's if:

their host name strings string-compare equal; or

A is a HDN string and has the form NB, where N is a non-empty name string, B has the form .B', and B' is a HDN string. (So, x.y.com domain-matches .Y.com but not Y.com.)

A host isn't in a domain (RFC 2965 sec. 3.3.2) if:

The value for the Domain attribute contains no embedded dots, and the value is not .local.

The effective host name that derives from the request-host does not domain-match the Domain attribute.

The request-host is a HDN (not IP address) and has the form HD, where D is the value of the Domain attribute, and H is a string that contains one or more dots.

Examples:

A Set-Cookie2 from request-host y.x.foo.com for Domain=.foo.com would be rejected, because H is y.x and contains a dot.

A Set-Cookie2 from request-host x.foo.com for Domain=.foo.com would be accepted.

A Set-Cookie2 with Domain=.com or Domain=.com., will always be rejected, because there is no embedded dot.

A Set-Cookie2 with Domain=ajax.com will be accepted, and the value for Domain will be taken to be .ajax.com, because a dot gets prepended to the value.

A Set-Cookie2 from request-host example for Domain=.local will be accepted, because the effective host name for the request- host is example.local, and example.local domain-matches .local.

Parameters:: domain - the domain name to check host name with; host - the host name in question
Returns:: true if they domain-matches; false if not

toString

public String toString()

Constructs a cookie header string representation of this cookie, which is in the format defined by corresponding cookie specification, but without the leading "Cookie:" token.

Overrides:: toString in class Object

Returns:: a string form of the cookie. The string has the defined format

equals

public boolean equals(Object obj)

Test the equality of two http cookies.

The result is true only if two cookies come from same domain (case-insensitive), have same name (case-insensitive), and have same path (case-sensitive).

Overrides:: equals in class Object

Parameters:: obj - the reference object with which to compare.
Returns:: true if 2 http cookies equal to each other; otherwise, false
See Also:: Object.hashCode(), Hashtable

hashCode

public int hashCode()

Return hash code of this http cookie. The result is the sum of hash code value of three significant components of this cookie: name, domain, and path. That is, the hash code is the value of the expression:

getName().toLowerCase().hashCode()
+ getDomain().toLowerCase().hashCode()
+ getPath().hashCode()

Overrides:: hashCode in class Object

Returns:: this http cookie's hash code
See Also:: Object.equals(java.lang.Object), Hashtable

clone

public Object clone()

Create and return a copy of this object.

Overrides:: clone in class Object

Returns:: a clone of this http cookie
See Also:: Cloneable