java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet

在写springMVC时，导入所有需要的包后，运行程序，控制台报以下错误：

严重: Servlet [springDispatcherServlet] in web application [/SpringMVC-1] threw load() exception
java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)
at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:518)
at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:499)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:118)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1091)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1027)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5038)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5348)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:725)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:587)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1798)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

随便在一个java文件中都无法import org.springframework.web.servlet.DispatcherServlet，这个类主要是在spring-webmvc jar包下，所有导入的jar包如下：

都已经导入，没有问题。但是实际上还要把依赖都加进classpath下。步骤：

项目右击-->properties-->Deployment Assembly-->add-->Java Build Path Entries-->导入所有依赖的Jar包，重新start tomcat即可。