Unsupported major.minor version 52.0
大概的意思是項目在eclipce中是用1.8編譯的，服務器上使用的1.7，所以會報錯
解決：把本地的jdk和jre改為1.7，在eclipce中引用1.7的jdk和jre重新clean項目，運行沒錯，
然後打成war包發到服務器上，這時的項目是用1.7編譯的，和服務器上jdk版本一致，所以運行就正常了
下面是異常代碼：
七月 24, 2017 3:42:28 下午 org.apache.catalina.core.AprLifecycleListener init
信息: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
七月 24, 2017 3:42:28 下午 org.apache.coyote.http11.Http11Protocol init
信息: Initializing Coyote HTTP/1.1 on http-58181
七月 24, 2017 3:42:28 下午 org.apache.catalina.startup.Catalina load
信息: Initialization processed in 630 ms
七月 24, 2017 3:42:28 下午 org.apache.catalina.core.StandardService start
信息: Starting service Catalina
七月 24, 2017 3:42:28 下午 org.apache.catalina.core.StandardEngine start
信息: Starting Servlet Engine: Apache Tomcat/6.0.37
七月 24, 2017 3:42:28 下午 org.apache.catalina.startup.HostConfig deployDirectory
信息: Deploying web application directory hunanidcalarm
七月 24, 2017 3:42:28 下午 org.apache.catalina.loader.WebappClassLoader validateJarFile
信息: validateJarFile(/opt/NmsAPP/Ultra-CUAlarm/webapps/hunanidcalarm/WEB-INF/lib/javax.servlet-api-3.1.0.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class
2017/07/24 15:42:29 INFO ContextLoader Root WebApplicationContext: initialization started
2017/07/24 15:42:30 INFO AbstractApplicationContext Refreshing Root WebApplicationContext: startup date [Mon Jul 24 15:42:30 CST 2017]; root of context hierarchy
2017/07/24 15:42:30 INFO XmlBeanDefinitionReader Loading XML bean definitions from class path resource [conf/applicationContext.xml]
2017/07/24 15:42:30 WARN AbstractApplicationContext Exception encountered during context initialization - cancelling refresh attempt
org.springframework.beans.factory.CannotLoadBeanClassException: Error loading class [com.ultrapower.hunan.lvwangwebserver.service.impl.LvWangServiceImpl] for bean with name ‘lvWangServiceImpl‘ defined in file [/opt/NmsAPP/Ultra-CUAlarm/webapps/hunanidcalarm/WEB-INF/classes/com/ultrapower/hunan/lvwangwebserver/service/impl/LvWangServiceImpl.class]: problem with class file or dependent class; nested exception is java.lang.UnsupportedClassVersionError: com/ultrapower/hunan/lvwangwebserver/service/impl/LvWangServiceImpl : Unsupported major.minor version 52.0 (unable to load class com.ultrapower.hunan.lvwangwebserver.service.impl.LvWangServiceImpl)
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1331)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:622)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:591)
at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1397)
at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:968)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:735)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:434)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4206)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4705)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:324)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
at org.apache.catalina.core.StandardService.start(StandardService.java:525)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
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:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by: java.lang.UnsupportedClassVersionError: com/ultrapower/hunan/lvwangwebserver/service/impl/LvWangServiceImpl : Unsupported major.minor version 52.0 (unable to load class com.ultrapower.hunan.lvwangwebserver.service.impl.LvWangServiceImpl)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2858)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1159)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1647)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
at org.springframework.util.ClassUtils.forName(ClassUtils.java:249)
at org.springframework.beans.factory.support.AbstractBeanDefinition.resolveBeanClass(AbstractBeanDefinition.java:395)
at org.springframework.beans.factory.support.AbstractBeanFactory.doResolveBeanClass(AbstractBeanFactory.java:1349)
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1320)
... 34 more
2017/07/24 15:42:30 ERROR ContextLoader Context initialization failed
org.springframework.beans.factory.CannotLoadBeanClassException: Error loading class [com.ultrapower.hunan.lvwangwebserver.service.impl.LvWangServiceImpl] for bean with name ‘lvWangServiceImpl‘ defined in file [/opt/NmsAPP/Ultra-CUAlarm/webapps/hunanidcalarm/WEB-INF/classes/com/ultrapower/hunan/lvwangwebserver/service/impl/LvWangServiceImpl.class]: problem with class file or dependent class; nested exception is java.lang.UnsupportedClassVersionError: com/ultrapower/hunan/lvwangwebserver/service/impl/LvWangServiceImpl : Unsupported major.minor version 52.0 (unable to load class com.ultrapower.hunan.lvwangwebserver.service.impl.LvWangServiceImpl)
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1331)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:622)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:591)
at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1397)
at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:968)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:735)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:434)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4206)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4705)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:324)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
at org.apache.catalina.core.StandardService.start(StandardService.java:525)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
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:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by: java.lang.UnsupportedClassVersionError: com/ultrapower/hunan/lvwangwebserver/service/impl/LvWangServiceImpl : Unsupported major.minor version 52.0 (unable to load class com.ultrapower.hunan.lvwangwebserver.service.impl.LvWangServiceImpl)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2858)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1159)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1647)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
at org.springframework.util.ClassUtils.forName(ClassUtils.java:249)
at org.springframework.beans.factory.support.AbstractBeanDefinition.resolveBeanClass(AbstractBeanDefinition.java:395)
at org.springframework.beans.factory.support.AbstractBeanFactory.doResolveBeanClass(AbstractBeanFactory.java:1349)
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1320)
... 34 more
七月 24, 2017 3:42:30 下午 org.apache.catalina.core.StandardContext start
嚴重: Error listenerStart
七月 24, 2017 3:42:30 下午 org.apache.catalina.core.StandardContext start
嚴重: Context [/hunanidcalarm] startup failed due to previous errors
七月 24, 2017 3:42:30 下午 org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
嚴重: The web application [/hunanidcalarm] appears to have started a thread named [Thread-2] but has failed to stop it. This is very likely to create a memory leak.
七月 24, 2017 3:42:30 下午 org.apache.coyote.http11.Http11Protocol start
信息: Starting Coyote HTTP/1.1 on http-58181
七月 24, 2017 3:42:30 下午 org.apache.jk.common.ChannelSocket init
信息: JK: ajp13 listening on /0.0.0.0:28009
七月 24, 2017 3:42:30 下午 org.apache.jk.server.JkMain start
信息: Jk running ID=0 time=0/86 config=null
七月 24, 2017 3:42:30 下午 org.apache.catalina.startup.Catalina start
信息: Server startup in 2109 ms
Unsupported major.minor version 52.0