原因：如果是用阿里云服务器，肯定是阿里面提示你要备案，导致后出出错页面显示的界面乱七八糟，去阿里云提交备案或备案接入大概在1小时内网站可以回复正常。
异常，暂未找到原因（部署到服务器出这种问题）
SEVERE: Servlet.service() for servlet [] in context with path [] threw exception
java.lang.IllegalStateException: Cannot call sendError() after the response has been committed
at org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:451)
at javax.servlet.http.HttpServletResponseWrapper.sendError(HttpServletResponseWrapper.java:120)
at net.bull.javamelody.FilterServletResponseWrapper.sendError(FilterServletResponseWrapper.java:91)
at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:771)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:506)
at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:102)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:153)
at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:131)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:662)
贴几个找到类似错误的地址：
http://struts.1045723.n5.nabble.com/SEVERE-Servlet-service-for-servlet-default-threw-exception-java-lang-IllegalStateException-td4632219.html
好像不是struts的bug
https://issues.apache.org/jira/browse/WW-3106?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel