求大佬帮忙看看，为什么javax.servlet.ServletContextAttributeEvent cannot be cast to javax.servlet.ServletContext

最新推荐文章于 2023-01-18 20:49:46 发布

原创最新推荐文章于 2023-01-18 20:49:46 发布 · 243 阅读

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严重: 属性事件监听器引发的异常
java.lang.ClassCastException: javax.servlet.ServletContextAttributeEvent cannot be cast to javax.servlet.ServletContext
at com.listener.MyServletContextListener.attributeReplaced(MyServletContextListener.java:23)
at org.apache.catalina.core.ApplicationContext.setAttribute(ApplicationContext.java:751)
at org.apache.catalina.core.ApplicationContextFacade.setAttribute(ApplicationContextFacade.java:399)
at com.servlet.EventTestServlet.doGet(EventTestServlet.java:18)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol $C o n n e c t i o n H a n d l e r . p r o c e s s (A b s t r a c t P r o t o c o l . j a v a : 834) a t o r g . a p a c h e . t o m c a t . u t i l . n e t . N i o E n d p o i n t$ SocketProcessor.doRun(NioEndpoint.java:1415)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor $W o r k e r . r u n (T h r e a d P o o l E x e c u t o r . j a v a : 624) a t o r g . a p a c h e . t o m c a t . u t i l . t h r e a d s . T a s k T h r e a d$ WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
`package com.listener;

import java.util.Date;
import javax.servlet.*;

public final class MyServletContextListener implements ServletContextListener,ServletContextAttributeListener{
private ServletContext context = null;

public void contextInitialized(ServletContextEvent scae){
	System.out.println("应用程序启动时间:" + new Date());
}
public void contextDestroyed(ServletContextEvent scae){
	System.out.println("应用程序关闭时间:" + new Date());
}
public void attributeAdded(ServletContextAttributeEvent scae){
	System.out.println("添加了一个上下文属性:"+scae.getName() + "="+scae.getValue());
}
public void attributeRemoved(ServletContextAttributeEvent scae){
	System.out.println("删除了一个上下文属性:"+scae.getName() + "=" + scae.getValue());
}
public void attributeReplaced(ServletContextAttributeEvent scae){
	System.out.print("修改了一个上下文属性,旧值: "+scae.getName() + "=" + scae.getValue());
	System.out.println(" ,新值: "+scae.getName() + "=" + ((ServletContext) scae).getAttribute(scae.getName()));
}

}
`