Class Cookie
java.lang.Object
  |
  +--javax.servlet.http.Cookie

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public class Cookie
extends java.lang.Object
implements java.lang.Cloneable

ãCreates 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. 

ɣA 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(javax.servlet.http.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. 

 ע 

     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. 



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Cookie 
Cookie(java.lang.String name, java.lang.String value)  //Constructs a cookie with a specified name and value. 

Ҫ
 java.lang.Object clone() // java.lang.Object.clone  a copy of this cookie. 
 java.lang.String getComment() //Returns the comment describing the purpose of this cookie, 
				//or null if the cookie has no comment. 
 java.lang.String getDomain()  //Returns the domain name set for this cookie. 
 int getMaxAge()  //Returns the maximum age of the cookie, specified in seconds, 
		  //By default, -1 indicating the cookie will persist until browser shutdown. 
 java.lang.String getName()   //Returns the name of the cookie. 
 java.lang.String getPath()   //Returns the path on the server to which the browser returns this 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. 
 java.lang.String getValue()  //Returns the value of the cookie. 
 int getVersion()  //Returns the version of the protocol this cookie complies with. 
 void setComment(java.lang.String purpose)  //Specifies a comment that describes a cookie's purpose. 
 void setDomain(java.lang.String pattern)   //Specifies the domain within which this cookie should be presented. 
 void setMaxAge(int expiry)   //Sets the maximum age of the cookie in seconds. 
 void setPath(java.lang.String uri)   //Specifies a path for the cookie to which the client should return the cookie. 
 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(java.lang.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. 

