tomcat服务器-重新部署后报错org.xml.sax.SAXParseException

今天把公司的项目放测试服务器上运行准备测试，但部署完毕后出现如下异常：

Mar 22, 2017 6:17:02 PM org.apache.naming.NamingContext lookup
WARNING: Unexpected exception resolving reference
org.xml.sax.SAXParseException; lineNumber: 42; columnNumber: 61; The entity name must immediately follow the '&' in the entity reference.
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1239)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:648)
at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1595)
at org.apache.catalina.users.MemoryUserDatabase.open(MemoryUserDatabase.java:424)
at org.apache.catalina.users.MemoryUserDatabaseFactory.getObjectInstance(MemoryUserDatabaseFactory.java:102)
at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:141)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:321)
at org.apache.naming.NamingContext.lookup(NamingContext.java:848)
at org.apache.naming.NamingContext.lookup(NamingContext.java:173)
at org.apache.catalina.realm.UserDatabaseRealm.startInternal(UserDatabaseRealm.java:253)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.realm.CombinedRealm.startInternal(CombinedRealm.java:236)
at org.apache.catalina.realm.LockOutRealm.startInternal(LockOutRealm.java:120)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1105)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:758)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.startup.Catalina.start(Catalina.java:693)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)

Mar 22, 2017 6:17:02 PM org.apache.catalina.realm.UserDatabaseRealm startInternal
SEVERE: Exception looking up UserDatabase under key UserDatabase
javax.naming.NamingException: The entity name must immediately follow the '&' in the entity reference.
at org.apache.naming.NamingContext.lookup(NamingContext.java:865)
at org.apache.naming.NamingContext.lookup(NamingContext.java:173)
at org.apache.catalina.realm.UserDatabaseRealm.startInternal(UserDatabaseRealm.java:253)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.realm.CombinedRealm.startInternal(CombinedRealm.java:236)
at org.apache.catalina.realm.LockOutRealm.startInternal(LockOutRealm.java:120)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1105)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:758)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.startup.Catalina.start(Catalina.java:693)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)

Mar 22, 2017 6:17:02 PM org.apache.catalina.realm.CombinedRealm startInternal
SEVERE: Failed to start "org.apache.catalina.realm.UserDatabaseRealm/1.0" realm
org.apache.catalina.LifecycleException: Failed to start component [Realm[UserDatabaseRealm]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
at org.apache.catalina.realm.CombinedRealm.startInternal(CombinedRealm.java:236)
at org.apache.catalina.realm.LockOutRealm.startInternal(LockOutRealm.java:120)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1105)
94fe

at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:758)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.startup.Catalina.start(Catalina.java:693)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)
Caused by: org.apache.catalina.LifecycleException: No UserDatabase component found under key UserDatabase
at org.apache.catalina.realm.UserDatabaseRealm.startInternal(UserDatabaseRealm.java:262)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
... 17 more

因为笔者对配置文件的变动内容知道的比较清楚，大致的排查一遍后发现并没有错误，于是又上了一个新的war包，仍然有错。只好从头到尾查看日志信息，希望能找到不一样的报错。最后发现是端口已经被占用，使用ps -ef|grep tomcat找到被占用的端口，kill -9 端口号。然后重新启动项目，解决！