unexpected ClassCastException with uniqueResult() method

stefanhendriks · **Joined:** Sun Nov 11, 2007 3:41 pm **Posts:** 3

The problem
I want a very simple login procedure, and i use database records for storing usernames and passwords.

I have a HQL named query defined, and it all gets executed well. I also have one result back for my test user account (username='test' and password='test').

When i do query.uniqueResult(); , it returns an Object[] which represents a row. I would expect it was mapped my persistent class User which is mapped and so forth.

So, what am i doing wrong here? The classcastexception itself is explainable, since i can't cast an Object[] to a User class. But why is hibernate not doing this?

Thanks in advance for any help given!

Hibernate version:
version 3.2.5

Mapping documents:
User.hbm.xml

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="nl.database.hibernate.persistence.User" table="USERS">

        <id name="id" column="ID">
            <generator class="native"/>
        </id>

        <property name="username" type="string" column="USERNAME"/>
        <property name="password" type="string" column="PASSWORD"/>
    </class>
   
   <sql-query name="getUserByUsernamePassword">
      select * from users where username = ? and password = ?
   </sql-query>
</hibernate-mapping>

and the code:

Code:

package nl.database.hibernate.persistence;

public class User implements java.io.Serializable {

   private Integer id;

    private String username;
    private String password;
    
    public User() {}

    public Integer getId() {
        return id;
    }

    private void setId(Integer id) {
        this.id = id;
    }

    public void setUsername(String username) {
       this.username = username;
    }
    
    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }
    
    public void setPassword(String password) {
       this.password = password;
    }
    
    public String toString() {
       return "Id=" + id + " | Username= " + username + " | Password = " + password;
    }

}

Code between sessionFactory.openSession() and session.close():

Code:

boolean mayLogin = false;
         Session session = HibernateFactory.getSessionFactory().openSession();
         try {
            
            // nl.database.hibernate.persistence.Users.
             Query query = session.getNamedQuery("getUserByUsernamePassword");
             query.setString(0, username);
             query.setString(1, password);
      
             logger.debug("Fetching a user from the database");
             User aUser = (User)query.uniqueResult();
             
             if (aUser != null) {
                logger.debug(aUser.toString());
                mayLogin = true;
             } else {
                logger.debug("No user found with username = " + username + " and password " + password);
             }
             
         } catch(Exception e ) {
            logger.debug(e);
         } finally {
            logger.debug("HIBERNATE: Closing session");
            session.close();            
         }

Full stack trace of any exception that occurs:
20:30:58,666 DEBUG [AbstractBatcher] preparing statement
20:30:58,688 DEBUG [StringType] binding 'test' to parameter: 1
20:30:58,691 DEBUG [StringType] binding 'test' to parameter: 2
20:30:58,695 DEBUG [AbstractBatcher] about to open ResultSet (open ResultSets: 0, globally: 0)
20:30:58,720 DEBUG [Loader] processing result set
20:30:58,723 DEBUG [Loader] result set row: 0
20:30:58,726 DEBUG [Loader] result row:
20:30:58,729 DEBUG [IntegerType] returning '1' as column: ID
20:30:58,732 DEBUG [StringType] returning 'test' as column: USERNAME
20:30:58,735 DEBUG [StringType] returning 'test' as column: PASSWORD
20:30:58,738 DEBUG [Loader] done processing result set (1 rows)
20:30:58,741 DEBUG [AbstractBatcher] about to close ResultSet (open ResultSets: 1, globally: 1)
20:30:58,744 DEBUG [AbstractBatcher] about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
20:30:58,747 DEBUG [AbstractBatcher] closing statement
20:30:58,755 DEBUG [StatefulPersistenceContext] initializing non-lazy collections
20:30:58,761 DEBUG [JDBCContext] after autocommit
20:30:58,764 DEBUG [ConnectionManager] aggressively releasing JDBC connection
20:30:58,768 DEBUG [ConnectionManager] releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
20:30:58,774 DEBUG [DriverManagerConnectionProvider] returning connection to pool, pool size: 1
20:30:58,776 DEBUG [DoLoginHandler] java.lang.ClassCastException: [Ljava.lang.Object;
20:30:58,779 DEBUG [DoLoginHandler] HIBERNATE: Closing session
20:30:58,782 DEBUG [SessionImpl] closing session
20:30:58,785 DEBUG [ConnectionManager] connection already null in cleanup : no action

Name and version of the database you are using:
mySQL

The generated SQL (show_sql=true):
See above

stefanhendriks · **Joined:** Sun Nov 11, 2007 3:41 pm **Posts:** 3

Additional information:
When doing it the other way around. I can succesfully save a User by doing:

Code:

User aNewUser = new User();
aNewUser.setPassword(password);
aNewUser.setUsername(username);
session.beginTransaction();
session.save(aNewUser);
session.getTransaction().commit();

max · **Posted:** Sun Nov 11, 2007 7:15 pm

your query is an native SQL query returning the value of the columns you are asking about. use a hql query or map the native sql query correctly; see the docs.

stefanhendriks · **Joined:** Sun Nov 11, 2007 3:41 pm **Posts:** 3

Unbelievable i did not see that in the first place. Probably too much staring at
the code for too long and too late :)

It works as a charm now! Thanks!