Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.

A.9 Session Tracking

531

  getDomain/setDomain: lets you specify domain to which cookie 

applies. Current host must be part of domain specified.

  getMaxAge/setMaxAge: gets/sets the cookie expiration time (in 

seconds). If you fail to set this, cookie applies to current browsing 

session only. See 

LongLivedCookie

 helper class (Section 8.5).

  getName/setName: gets/sets the cookie name. For new cookies, you 

supply name to constructor, not to 

setName

. For incoming cookie array, 

you use 

getName

 to find the cookie of interest.

  getPath/setPath: gets/sets the path to which cookie applies. If 

unspecified, cookie applies to URLs that are within or below directory 

containing current page.

  getSecure/setSecure: gets/sets flag indicating whether cookie should 

apply only to SSL connections or to all connections.

  getValue/setValue: gets/sets value associated with cookie. For new 

cookies, you supply value to constructor, not to 

setValue

. For incoming 

cookie array, you use 

getName

 to find the cookie of interest, then call 

getValue

 on the result.

  getVersion/setVersion: gets/sets the cookie protocol version. Version 0 

is the default; stick with that until browsers start supporting version 1.

A.9 Session Tracking

Looking Up Session Information: getValue

HttpSession session = request.getSession(true);

ShoppingCart cart =

(ShoppingCart)session.getValue("shoppingCart");

if (cart == null) { // No cart already in session

cart = new ShoppingCart();

session.putValue("shoppingCart", cart);

}

doSomethingWith(cart);

Associating Information with a Session: putValue

HttpSession session = request.getSession(true);

session.putValue("referringPage", request.getHeader("Referer"));

ShoppingCart cart =

(ShoppingCart)session.getValue("previousItems");

if (cart == null) { // No cart already in session

cart = new ShoppingCart();

session.putValue("previousItems", cart);

}

String itemID = request.getParameter("itemID");

if (itemID != null) {

cart.addItem(Catalog.getItem(itemID));

}

Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com.

Servlet and JSP training courses by book's author: courses.coreservlets.com.