Question

private ILogin results;

    public ILogin authenticate(Login login) {
        System.out.println(login);
        System.out.println(login.getEmail());
        String query = "SELECT email, id FROM Login WHERE email='"
        + login.getEmail() + "' AND password='" + login.getPassword() + "'";
        results = getHibernateTemplate().find(query);
        System.out.println(results);
        return results;
    }

How do i change results = getHibernateTemplate().find(query); I get the error in this line. But i want that in ILogin type not of List type. How do i do an Type Conversion here.

Answer 1

The problem isn’t the type conversion per se – it’s that you’ve executed a query which may return multiple results, but you only want a single result.

You probably want to check that the resulting list has exactly one value (0 means login not found; more than 1 probably means there’s a problem in your data somewhere) and then return that first value (return (ILogin) list.get(0);).

As a slightly separate matter, you shouldn’t be including the data directly in your query like that, IMO. Use query parameters, which is pretty easy in Hibernate:

 String query = "SELECT email, id FROM Login WHERE email=? AND password=?";
 Object[] parameters = { login.getEmail(), login.getPassword() };
 List results = getHibernateTemplate().find(query, parameters);
 if (results.size() != 1) {
     // Probably throw an exception
 }
 // I'm assuming your mapping has been set up appropriately such that
 // the returned value will *be* an `ILogin`.
 return (ILogin) results.get(0);

Finally, you almost certainly don’t want results to be an instance variable – it should probably be a local variable, as per my example above.