//CategoryService接口 
public interface CategoryService extends BaseService<Category> { 
 //省略其他方法…… 
 //根据boelen值查询热点或非热点类别 
 public List<Category> queryByHot(boolean hot); 
} 
 
@SuppressWarnings("unchecked") 
@Service("categoryService") 
public class CategoryServiceImpl extends BaseServiceImpl<Category> implements CategoryService { 
 
 //省略其他方法…… 
 
 @Override 
 public List<Category> queryByHot(boolean hot) { 
  String hql = "from Category c where c.hot=:hot"; 
  return getSession().createQuery(hql) 
   .setBoolean("hot", hot) 
   .list(); 
 } 
} 
//ProductService接口 
public interface ProductService extends BaseService<Product> { 
  
 //省略其他方法…… 
 //根据热点类别查询推荐商品（仅仅查询前4个） 
 public List<Product> querByCategoryId(int cid); 
} 
 
@SuppressWarnings("unchecked") 
@Service("productService") 
public class ProductServiceImpl extends BaseServiceImpl<Product> implements ProductService { 
 
 //省略其他方法…… 
 
 @Override 
 public List<Product> querByCategoryId(int cid) { 
  String hql = "from Product p join fetch p.category " 
    + "where p.commend=true and p.open=true and p.category.id=:cid order by p.date desc"; 
  return getSession().createQuery(hql) 
   .setInteger("cid", cid) 
   .setFirstResult(0) 
   .setMaxResults(4) 
   .list(); 
 } 
 
} 

//@Component //监听器是web层的组件，它是tomcat实例化的，不是Spring实例化的。不能放到Spring中 
public class InitDataListener implements ServletContextListener { 
  
 private ProductService productService = null; 
 private CategoryService categoryService = null; 
 private ApplicationContext context = null; 
  
 @Override 
 public void contextDestroyed(ServletContextEvent event) { 
  // TODO Auto-generated method stub 
 
 } 
 
 @Override 
 public void contextInitialized(ServletContextEvent event) { 
 
  context = WebApplicationContextUtils.getWebApplicationContext(event.getServletContext());   
  categoryService = (CategoryService) context.getBean("categoryService");//加载类别信息   
  productService = (ProductService) context.getBean("productService");//加载商品信息 
 
  List<List<Product>> bigList = new ArrayList<List<Product>>(); //bigList中存放一个装有Category类的list 
  // 1. 查询出热点类别 
  for(Category category : categoryService.queryByHot(true)) { 
   //根据热点类别id获取推荐商品信息 
   List<Product> lst = productService.querByCategoryId(category.getId()); 
   bigList.add(lst); //将装有category的list放到bigList中 
  } 
  // 2. 把查询的bigList交给application内置对象 
  event.getServletContext().setAttribute("bigList", bigList); 
 } 
 
}