本文介绍了tomcat 8 嵌入式模式下的 JasperInitializer的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在将嵌入式 tomcat 应用程序从 7.0.59 迁移到 tomcat 8.0.20当我启动嵌入式服务器并尝试访问主页时更新 Tomcat 版本后，我收到 NullPOinterException
I'm in the process of migrating embedded tomcat application from 7.0.59 to tomcat 8.0.20After updating the Tomcat version when I'm starting the embedded server and try to access the home page I'm getting a NullPOinterException
ERROR {org.apache.catalina.core.ApplicationDispatcher} - Servlet.service() for servlet bridgeservlet threw exception
java.lang.NullPointerException
at org.apache.jasper.JspCompilationContext.getTldResourcePath(JspCompilationContext.java:536)
at org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:410)
at org.apache.jasper.compiler.Parser.parseDirective(Parser.java:469)
at org.apache.jasper.compiler.Parser.parseElements(Parser.java:1430)
at org.apache.jasper.compiler.Parser.parse(Parser.java:139)
at org.apache.jasper.compiler.ParserController.doParse(ParserController.java:227)
at org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)
at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:570)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:356)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.wso2.carbon.ui.JspServlet.service(JspServlet.java:155)
at org.wso2.carbon.ui.TilesJspServlet.service(TilesJspServlet.java:80)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.eclipse.equinox.http.helper.ContextPathServletAdaptor.service(ContextPathServletAdaptor.java:37)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:128)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:68)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.wso2.carbon.tomcat.ext.servlet.DelegationServlet.service(DelegationServlet.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
at org.eclipse.equinox.http.servlet.internal.RequestDispatcherAdaptor.forward(RequestDispatcherAdaptor.java:30)
at org.eclipse.equinox.http.helper.ContextPathServletAdaptor$RequestDispatcherAdaptor.forward(ContextPathServletAdaptor.java:362)
at org.apache.tiles.servlet.context.ServletTilesRequestContext.forward(ServletTilesRequestContext.java:198)
at org.apache.tiles.servlet.context.ServletTilesRequestContext.dispatch(ServletTilesRequestContext.java:185)
at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:419)
at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:370)
at org.wso2.carbon.ui.action.ActionHelper.render(ActionHelper.java:52)
at org.wso2.carbon.ui.TilesJspServlet.service(TilesJspServlet.java:101)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.eclipse.equinox.http.helper.ContextPathServletAdaptor.service(ContextPathServletAdaptor.java:37)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:128)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:68)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.wso2.carbon.tomcat.ext.servlet.DelegationServlet.service(DelegationServlet.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.wso2.carbon.tomcat.ext.filter.CharacterSetFilter.doFilter(CharacterSetFilter.java:61)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.wso2.carbon.tomcat.ext.valves.CompositeValve.continueInvocation(CompositeValve.java:99)
at org.wso2.carbon.tomcat.ext.valves.TomcatValveContainer.invokeValves(TomcatValveContainer.java:49)
at org.wso2.carbon.tomcat.ext.valves.CompositeValve.invoke(CompositeValve.java:62)
at org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:159)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at org.wso2.carbon.tomcat.ext.valves.CarbonContextCreatorValve.invoke(CarbonContextCreatorValve.java:57)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
调试tomcat8源码，发现EmbeddedServletOption中的tldCache为空.这是由 JasperInitializer
I debug the tomcat8 source and found that tldCache inside the EmbeddedServletOption is null. This is been set by the onStartup method in the JasperInitializer
我该怎么做才能确保它被调用或者我如何手动调用 org.apache.jasper.servlet.JasperInitializer.onStartup在网络应用启动期间?
What can I do to make sure that it get invokeor how can I manually invoke org.apache.jasper.servlet.JasperInitializer.onStartupduring web app startup?
我在应用程序中嵌入了 tomcat 8.
I'm embedding tomcat 8 inside the application.
推荐答案
这个问题的解决方案有点隐蔽，似乎没有记录，但有时可以用一行代码解决.
The solution to this issue is somewhat hidden and doesn't seem to be documented but it can sometimes be solved with one line of code.
context.addServletContainerInitializer(new JasperInitializer(), null);
我承认服务器在添加后启动很慢，但它现在可以正常工作了.
I admit the server is slow to start once this is added, but it is now functional.
这篇关于tomcat 8 嵌入式模式下的 JasperInitializer的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！