项目部署在tomcat下，启动的时候报错该怎么办？

1. 项目部署在tomcat下，启动的时候报错该怎么办？

原因：一启动就报错，是因为启动端口8080被占用了。
解决方法：查看8080端口被什么程序占用了，结束此程序释放8080端口，重启启动项目即可。
操作步骤如下：
1、在电脑桌面按下键盘上的win+R键，打开运行窗口，输入cmd，点击确定；

2、在打开的cmd窗口内输入netstat -ano|findstr 8080，查看正在使用8080端口的进程。

3、执行以下命令，结束进程taskkill /pid 25216 /f。

4、再次运行tomcat服务器，成功启动。

2. tomcat服务器加载报异常如何解决

在用Tomcat服务器发布一个由jsp，servlet等技术组成的web项目时，出现下面错误，
 
严重 [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.ContainerBase.addChildInternal ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]at org.apache.catalina.util.LifecycleBase.handleSubClassException(LifecycleBase.java:441)at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:198)at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:740)at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:716)at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:703)at org.apache.catalina.startup.HostConfig.manageApp(HostConfig.java:1729)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:287)at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:456)at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:405)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:287)at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)at sun.rmi.transport.Transport$1.run(Transport.java:200)at sun.rmi.transport.Transport$1.run(Transport.java:197)at java.security.AccessController.doPrivileged(Native Method)at sun.rmi.transport.Transport.serviceCall(Transport.java:196)at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)at java.security.AccessController.doPrivileged(Native Method)at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)at java.lang.Thread.run(Thread.java:748)Caused by: java.lang.IllegalArgumentException: Invalid  [active] in servlet mappingat org.apache.catalina.core.StandardContext.addServletMappingDecoded(StandardContext.java:3105)at org.apache.catalina.Context.addServletMappingDecoded(Context.java:879)at org.apache.catalina.startup.ContextConfig.configureContext(ContextConfig.java:1386)at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1197)at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:775)at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299)at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5003)at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)... 42 more
 
查看上面错误提示，可以看到这么一句：Caused by: java.lang.IllegalArgumentException: Invalid  [active] in servlet mapping
于是进入 web.xml文件查看配置文件的 ，发现文件是
ActiveServletactive
在active前面少了一个“/”,加上/后变为
ActiveServlet/active重新启动Tomcat服务器，问题解决。

3. tomcat下java web工程报错

感觉是那个javaee.jar跟tomcat有冲突，试试去掉看看还报不报错