How to cast an Object to an int

Question

How can I cast an Object to an int in java?

Answer 1

int[] getAdminIDList(String tableName, String attributeName, int value) throws SQLException {
    ArrayList list = null;
    Statement statement = conn.createStatement();
    ResultSet result = statement.executeQuery("SELECT admin_id FROM " + tableName + " WHERE " + attributeName + "='" + value + "'");
    while (result.next()) {
        list.add(result.getInt(1));
    }
    statement.close();
    int id[] = new int[list.size()];
    for (int i = 0; i < id.length; i++) {
        try {
            id[i] = ((Integer) list.get(i)).intValue();
        } catch(NullPointerException ne) {
        } catch(ClassCastException ch) {}
    }
    return id;
}
// enter code here

This code shows why ArrayList is important and why we use it. Simply casting int from Object. May be its helpful.

Answer 2

int i = (Integer) object; //Type is Integer.

int i = Integer.parseInt((String)object); //Type is String.

Answer 3

You have to cast it to an Integer (int's wrapper class). You can then use Integer's intValue() method to obtain the inner int.

Answer 4

Finally, the best implementation for your specification was found.

public int tellMyNumber(Object any) {
    return 42;
}

Answer 5

You can't. An int is not an Object.

Integer is an Object though, but I doubt that's what you mean.

Answer 6

@Deprecated
public static int toInt(Object obj)
{
    if (obj instanceof String)
    {
         return Integer.parseInt((String) obj);
    } else if (obj instanceof Number)
    {
         return ((Number) obj).intValue();
    } else
    {
         String toString = obj.toString();
         if (toString.matches("-?\d+"))
         {
              return Integer.parseInt(toString);
         }
         throw new IllegalArgumentException("This Object doesn't represent an int");
    }
}

As you can see, this isn't a very efficient way of doing it. You simply have to be sure of what kind of object you have. Then convert it to an int the right way.