Question

I am getting an error with Hibernate (I am not too familiar the API yet). Here is my code below:

public void retrieveToDB(String data){
    Session session = HibernateUtil.getSessionFactory().openSession();
    session.beginTransaction();

    Query q = session.createQuery("Select empName from Employee where empName = :emp");
    q.setParameter("emp", data);
    List result = q.list();

    Iterator iter = result.iterator();

    while(iter.hasNext()){
        Employee emp = (Employee) iter.next();
        String e = emp.getEmpName();
        System.out.println("THIS IS " +e);
    }



}     

I wanted to retrieve an employee name from employee table and put into a test string to be sent to the client side. But my problem is I am getting this error which I am very unfamiliar with:

  Exception in thread "Thread-0" java.lang.ClassCastException: java.lang.String cannot be cast to com.datadistributor.main.Employee

I tried to find some tutorials regarding lists handling in Hibernate but I keep finding the same (unhelpful) stuff. So far nothing I’ve tried has worked out, I hope someone can help me out.

ok i updated my code and i get again new error…is there anything wrong? i hope can get some help here

Answer 1

I think what you’re looking to do is something closer to this:

public void retrieveToDB(String data) {
    Session session = HibernateUtil.getSessionFactory().openSession();
    // I don't think you need to start a transaction just to do a SELECT statement
    //session.beginTransaction();

    Query q = session.createQuery("SELECT e from Employee e where e.empName = :empname");
    q.setParameter("empname", data);
    List results = (List) q.list();

    String test = null;
    Iterator iter = results.iterator();

    while (iter.hasNext()) {
        Employee emp = (Employee) iter.next();
        test = emp.getEmpName();
    }

    sendMsg(test);
}

There’s no need to store your query’s results into an enclosing List (or ArrayList) if you’re just planning to unwrap it to get at the underlying Employee object.