MAVEN WEB 项目运行异常记录001

在构建maven web项目时，启动tomcat正常，但是访问项目时报错，tomcat版本为apache-tomcat-8.0.14,错误如下：

30-Apr-2017 16:53:09.123 SEVERE [http-apr-8888-exec-2] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [jsp] in context with path [/OnlineExam] threw exception [java.lang.LinkageError: loader constraint violation: when resolving method "org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(Ljavax/servlet/ServletConfig;)Lorg/apache/tomcat/InstanceManager;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of java/net/URLClassLoader) for the method's defining class, org/apache/jasper/runtime/InstanceManagerFactory, have different Class objects for the type org/apache/tomcat/InstanceManager used in the signature] with root cause java.lang.LinkageError: loader constraint violation: when resolving method "org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(Ljavax/servlet/ServletConfig;)Lorg/apache/tomcat/InstanceManager;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of java/net/URLClassLoader) for the method's defining class, org/apache/jasper/runtime/InstanceManagerFactory, have different Class objects for the type org/apache/tomcat/InstanceManager used in the signatureat org.apache.jsp.index_jsp._jspInit(index_jsp.java:32)at org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:49)at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:180)at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)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.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.StandardWrapperValve.invoke(StandardWrapperValve.java:219)at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:277)at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2403)at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2392)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)30-Apr-2017 16:53:09.689 SEVERE [http-apr-8888-exec-6] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [jsp] in context with path [/OnlineExam] threw exception [java.lang.LinkageError: loader constraint violation: when resolving method "org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(Ljavax/servlet/ServletConfig;)Lorg/apache/tomcat/InstanceManager;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of java/net/URLClassLoader) for the method's defining class, org/apache/jasper/runtime/InstanceManagerFactory, have different Class objects for the type org/apache/tomcat/InstanceManager used in the signature] with root cause java.lang.LinkageError: loader constraint violation: when resolving method "org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(Ljavax/servlet/ServletConfig;)Lorg/apache/tomcat/InstanceManager;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of java/net/URLClassLoader) for the method's defining class, org/apache/jasper/runtime/InstanceManagerFactory, have different Class objects for the type org/apache/tomcat/InstanceManager used in the signatureat org.apache.jsp.index_jsp._jspInit(index_jsp.java:32)at org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:49)at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:180)at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)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.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.StandardWrapperValve.invoke(StandardWrapperValve.java:219)at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:277)at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2403)at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2392)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)

分析原因：看错误提示好像与JSP解析有关，分析错误可以猜想是 jasper 相关的jar与pom.xml中引用的jar包存在冲突。

解决方案：删除tomcat lib目录中的jasper.jar 包，重新启动项目，可以运行。