null pointer exception when using @Autowired for sessionFactory to get data from database in DHXEventsManager

Question

When I use @Autowired annotation for SessionFactory to retrive data from the DB when using DHXEventsManager,java.lang.NullPointerException occurred.I can't fix it.Please anyone help!

package com.dhtmlx.booking.controller;
import javax.servlet.http.HttpServletRequest;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import com.dhtmlx.planner.DHXEv;
import com.dhtmlx.planner.DHXEventsManager;
import com.dhtmlx.planner.DHXStatus;
import com.dhtmlx.planner.data.DHXCollection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class CustomEventsManager extends DHXEventsManager {
 @Autowired
 SessionFactory sessionfactory;
        public CustomEventsManager(HttpServletRequest request) {
                        super(request);
        }

        public Iterable<DHXEv> getEvents() {

                        List<DHXEv> evs = new ArrayList<DHXEv>();
                        try {

 evs = sessionfactory.getCurrentSession().createCriteria(Event.class).list();
                        } catch (RuntimeException e) {
                                        e.printStackTrace();
                        } 

        return evs;
        }
      }