HttpSession session=request.getSession(true);
ArrayList previousItems=(ArrayList)session.getAttribute("previousItems");
if(previousItems == null){
previousItems=new ArrayList();
session.setAttribute("previousItems", previousItems);
}
String newItem=request.getParameter("newItem");
String title="Item Purchased";
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
out.println("
try {
synchronized(previousItems){
if(newItem !=null){
previousItems.add(newItem);
}
if(previousItems.isEmpty()){
out.println("No Items");
}else{
out.println("Items:");
out.println("
- ");
- "+(String)previousItems.get(i)+" ");
for(int i=0; i out.println("
}
out.println("
}
}
session.invalidate();
out.println("Back");
} finally {
out.close();
}
想请问一下这个怎么用cookie实现