如何将对象类型列表转换为对象数组

Question

I have to return array of objects from a method. The objects are initially held in a List of objects type. I am having difficulties in assigning values from list of objects to array of objects. How do I do that. Here is my code:

public User[] getUser() {

    User[] users = null;

    Session session = HibernateUtil.getSessionFactory().openSession();
    List<User> users = session.createQuery("from User").list();
    for (Iterator<User> iter = users.iterator(); iter.hasNext(); ) {
        User user = iter.next();
        //Here I need to assign User type object from list to array of objects
    }
    return users; // returning nothing so far
}

Answer 1

Switching back and forth from List s to arrays and vice versa can be done with the methods

User[] array = users.toArray( new User[usersList.size()] );//from list to array
List<User> usersList = Arrays.asList( userArray );//from array to list

See the javadoc ( List#toArray and Arrays#asList ) of those methods for more information

Answer 2

使用列表的toArray方法：

return users.toArray(new User[users.size]);

Answer 3

Would this solve your problem?

usersList = users.toArray(new User[users.size()]);

By the way you're using users twice in your code (as array and as list)