springboot集成OncePerRequestFilter，是什么原因？

1.springboot中我重写了一个filter，结果偶发性的出现空指针

2.

java.lang.NullPointerException: null
    at org.apache.catalina.connector.Request.notifyAttributeAssigned(Request.java:1555) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.catalina.connector.Request.setAttribute(Request.java:1541) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:540) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at javax.servlet.ServletRequestWrapper.setAttribute(ServletRequestWrapper.java:252) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at javax.servlet.ServletRequestWrapper.setAttribute(ServletRequestWrapper.java:252) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at javax.servlet.ServletRequestWrapper.setAttribute(ServletRequestWrapper.java:252) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.springframework.web.context.request.async.WebAsyncUtils.getAsyncManager(WebAsyncUtils.java:51) ~[spring-web-5.0.5.RELEASE.jar!/:5.0.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:928) ~[spring-webmvc-5.0.5.RELEASE.jar!/:5.0.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.5.RELEASE.jar!/:5.0.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) ~[spring-webmvc-5.0.5.RELEASE.jar!/:5.0.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.5.RELEASE.jar!/:5.0.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
--
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.tomcat.util.net.Nio2Endpoint$SocketProcessor.doRun(Nio2Endpoint.java:1697) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[?:1.8.0_171]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[?:1.8.0_171]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-8.5.29.jar!/:8.5.29]
    at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]