columnMap.put("user_id", userID);
columnMap.put("login_name", loginName);
columnMap.put("password", password);
columnMap.put("is_admin", new Boolean(isAdmin));
if (DBUtil.insert(con, "user", columnMap) != 1)
throw new DBException("new user could not insert to db.");
return new User(userID, loginName, isAdmin);
}