Remove session attributes which name starts from specific name

Question

In my servlet, if I want to remove a specific session attribute I run:

session.removeAttribute("user");

and I want to remove all of them:

session.invalidate();

How to remove only those session attributes which their name starts from a specific value? For example instead running:

session.removeAttribute("userDsdf");
session.removeAttribute("userSDFSF");
session.removeAttribute("userVSDfs");
session.removeAttribute("userESFDFS");

run something like session.removeAttribute("user%");

Answer 1

There's no method to do that work exactly, but you can do it yourself by enumerating attributes and filtering:

Enumeration<String> attributes = session.getAttributeNames();
while (attributes.hasMoreElements()) {
    String next = attributes.nextElement();
    if (!next.startsWith("user")) continue;
    session.removeAttribute(next);
}

Answer 2

You can go through attribute names with stream:

Collections.list(session.getAttributeNames()).stream()
        .filter(a -> a.startsWith("user"))
            .forEach(a -> session.removeAttribute(a));