在Servlet API中有一个ServletContextListener接口,它能够监听ServletContext对象的生命周期,实际上就是监听Web应用的生命周期。
当Servlet容器启动或终止Web应用时,会触发ServletContextEvent事件,该事件由 ServletContextListener 来处理。在 ServletContextListener 接口中定义了处理ServletContextEvent事件的两个方法。
contextInitialized(ServletContextEvent sce):当Servlet容器启动Web应用时调用该方法。在调用完该方法之后,容器再对Filter初始化,并且对那些在Web应用启动时就需要被初始化的Servlet进行初始化。
contextDestroyed(ServletContextEvent sce):当Servlet容器终止Web应用时调用该方法。在调用该方法之前,容器会先销毁所有的Servlet和Filter过滤器。
public class QuartzInitializerListener implements ServletContextListener {}
public class ContextLoaderListener extends ContextLoader implements ServletContextListener {}
下面在Quartz上通过ServletContextListener得到ServletContext,从而能在任务中得到ServletContext:
public class QuartzServletContextListener extends QuartzInitializerListener { public static final String MY_CONTEXT_NAME = "servletContext"; @Override public void contextDestroyed(ServletContextEvent sce) { // TODO Auto-generated method stub super.contextDestroyed(sce); } @Override public void contextInitialized(ServletContextEvent sce) { // TODO Auto-generated method stub super.contextInitialized(sce); ServletContext servletContext = sce.getServletContext(); StdSchedulerFactory factory = (StdSchedulerFactory) servletContext .getAttribute(QuartzInitializerListener.QUARTZ_FACTORY_KEY); try { factory.getScheduler().getContext() .put(QuartzServletContextListener.MY_CONTEXT_NAME, servletContext); } catch (SchedulerException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
Job中得到ServletContext:
public class XLSJob implements StatefulJob { public void execute(JobExecutionContext arg0) throws JobExecutionException { // TODO Auto-generated method stub try { ServletContext context = null; try { context = (ServletContext) arg0.getScheduler().getContext() .get(QuartzServletContextListener.MY_CONTEXT_NAME); } catch (SchedulerException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } WebApplicationContext conn=(WebApplicationContext)context.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE); } }
因为要监听ServletContext,最后在web.xml配置该监听:
<listener> <listener-class>x.x.x.QuartzServletContextListener</listener-class> </listener>