当把我的springMVC项目发到tomcat运行的时候，出现下列问题，开始我以为是我的JDK版本过低，我看下了，jdk8应该可以支持所有的低版本，因为项目最合适用jdk7，我又把jdk版本降低到jdk7；还是出现了这样的问题！出现的异常如下！
异常情况:
异常内容:
org.springframework.beans.factory.CannotLoadBeanClassException: Error loading class [controller.ItemsController3] for bean with name 'itemsController3' defined in file [D:\InstallSoftWare\tomcat\webapps\testspringmvc\WEB-INF\classes\controller\ItemsController3.class]: problem with class file or dependent class; nested exception is java.lang.UnsupportedClassVersionError: controller/ItemsController3 : Unsupported major.minor version 51.0 (unable to load class controller.ItemsController3)
org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1266)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:581)
org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1332)
org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:898)
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:588)
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:647)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:598)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:661)
org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:517)
org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:458)
org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:138)
javax.servlet.GenericServlet.init(GenericServlet.java:158)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:662)后来我反应过来，是我的tomcat中配置的jdk和项目中使用的jdk配置不一致，就出现了这种问题！我的tomcat中配置的jdk:
上面的jdk是1.6；而java编译器中的jdk是1.7，出现了编译器的版本不一致；
所以要将tomcat上的jdk改为1.7就不会出现问题了！当把tomcat上的jdk更新到1.7之后，上面出现的问题就不存在了！从而解决了这个异常！