对于某些不会变又经常需要用的数据的处理

import java.util.List;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import cn.itcast.oa.domain.Privilege;
import cn.itcast.oa.service.PrivilegeService;
public class InitListener implements ServletContextListener {
  public void contextInitialized(ServletContextEvent sce) {
    // 获取容器与相关的Service对象
    ApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(sce.getServletContext());
    PrivilegeService privilegeService = (PrivilegeService) ac.getBean("privilegeServiceImpl");
    // 准备数据：topPrivilegeList
    List<Privilege> topPrivilegeList = privilegeService.findTopList();
    System.out.println("size"+topPrivilegeList.size());
    sce.getServletContext().setAttribute("topPrivilegeList", topPrivilegeList);
    System.out.println("------------> 已准备数据 <------------");
  }
  public void contextDestroyed(ServletContextEvent arg0) {
  }
}