java.lang.IllegalStateException: class utils.filter.ContentFilter is not a javax.servlet.Filter

1、错误描写叙述

2016-01-12 11:27:01.787:WARN:oejuc.AbstractLifeCycle:FAILED ContentFilter: java.lang.IllegalStateException: class utils.filter.ContentFilter is not a 

javax.servlet.Filter
java.lang.IllegalStateException: class utils.filter.ContentFilter is not a javax.servlet.Filter
	at org.eclipse.jetty.servlet.FilterHolder.doStart(FilterHolder.java:97)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:768)
	at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:265)
	at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1242)
	at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:717)
	at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:494)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95)
	at org.eclipse.jetty.server.Server.doStart(Server.java:282)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at net.sourceforge.eclipsejetty.starter.embedded.JettyEmbeddedAdapter.start(JettyEmbeddedAdapter.java:67)
	at net.sourceforge.eclipsejetty.starter.common.AbstractJettyLauncherMain.launch(AbstractJettyLauncherMain.java:84)
	at net.sourceforge.eclipsejetty.starter.embedded.JettyEmbeddedLauncherMain.main(JettyEmbeddedLauncherMain.java:42)
2016-01-12 11:27:01.788:WARN:oejw.WebAppContext:Failed startup of context o.e.j.w.WebAppContext

{/,file:/E:/Java/workspaces/maven/src/main/webapp/},E:Javaworkspaces

mavensrcmainwebapp
java.lang.IllegalStateException: class utils.filter.ContentFilter is not a javax.servlet.Filter
	at org.eclipse.jetty.servlet.FilterHolder.doStart(FilterHolder.java:97)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:768)
	at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:265)
	at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1242)
	at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:717)
	at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:494)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95)
	at org.eclipse.jetty.server.Server.doStart(Server.java:282)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at net.sourceforge.eclipsejetty.starter.embedded.JettyEmbeddedAdapter.start(JettyEmbeddedAdapter.java:67)
	at net.sourceforge.eclipsejetty.starter.common.AbstractJettyLauncherMain.launch(AbstractJettyLauncherMain.java:84)
	at net.sourceforge.eclipsejetty.starter.embedded.JettyEmbeddedLauncherMain.main(JettyEmbeddedLauncherMain.java:42)
2016-01-12 11:27:01.871:INFO:oejs.AbstractConnector:Started SelectChannelConnector@0.0.0.0:8080

2、错误原因

3、解决的方法