Javaobject“连接”不适用于禁用的Cookies

Question

i am having a Problem with disabled Cookies. i am Having a page where a User logs in with his User account. The connection itself is saved in the session, if the login was sucessfull.

request.getSession().setAttribute("connection"  , connection);

the Object DBConnection, named connection in the Session, is an Object, which has got a static Connection con Object

protected static Connection con = null;

when the User logs in, the Connections gets established with

con = DriverManager.getConnection(url, this.user, this.password);

This also works with dectivated cookies. if was checking the Connection and the con Object i want to save with a System.out.println.

System.out.println(("DBConnection == null: " + connection == null));
System.out.println("Connection" connection.getCon());
//result ->
//DBConnection == null: false
//oracle.jdbc.driver.T4CConnection@15d51e5

So the Login was sucessfull. now the User leave this side and go to some other information Pages due to a button. in Here i need this connection again and i am getting it in a Servlet.

DBConnection connection = (DBConnection)request.getSession().getAttribute("connection");

with the Same System.out.println as before it gives the same result as before, when cookies are enabled. When cookies are disabled, it throws an Exception with this results:

DBConnection == null: false
java.lang.NullPointerException

So now my Question. Why does my connection break, when i have my cookies disabled? In my mind cookies don´t have anything to deal with the connection Object, or any other Object beeing saved within a JSP? The connection Object throwing the Nullpointer is the Object in the Package java.sql.Connection;

Answer 1

This problem is related on how does the application or web servers store the session id on the cliente side: they use cookies for this.

On how to enable session binding for disabled cookies clients, you could check this related question on this very same site: How can i do sessions in java if some one disables cookies in my browser?