解决通过Jetty WTP Plugin启动Jetty时报错：NoClassDefFoundError: org/objectweb/asm/ClassVisitor
测试环境：JDK1.6，jetty-distribution-8.1.8.v20121106
原因是：${JETTY_HOME}\lib\annotations下的两个包org.objectweb.asm-3.1.0.v200803061910.jar，javax.annotation-1.1.0.v201108011116.jar没有被包含进去。
添加包到Jetty运行环境中：
1，在Server视图里双击目标Jetty Server打开Overview。
2，在Overview里点击Open launch configuration打开配置页面。
3，选择名为Classpath的tab页面，单击User Entries。
4，在右边的按钮中单击Add External JARs...，最后通过文件浏览将${JETTY_HOME}\lib\annotations下的两个包org.objectweb.asm-3.1.0.v200803061910.jar，javax.annotation-1.1.0.v201108011116.jar加进去。
5，启动Jetty Server，错误消失。祝你成功！！
java.lang.NoClassDefFoundError: org/objectweb/asm/ClassVisitor ：
java.lang.NoClassDefFoundError: org/objectweb/asm/ClassVisitor at org.eclipse.jetty.annotations.AnnotationConfiguration.createAnnotationParser(AnnotationConfiguration.java:154) at org.eclipse.jetty.annotations.AnnotationConfiguration.configure(AnnotationConfiguration.java:105) at org.eclipse.jetty.webapp.WebAppContext.configure(WebAppContext.java:466) at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1245) at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:706) at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:492) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:39) at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:186) at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:494) at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:141) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:145) at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:56) at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:609) at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:540) at org.eclipse.jetty.util.Scanner.scan(Scanner.java:403) at org.eclipse.jetty.util.Scanner.doStart(Scanner.java:337) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.doStart(ScanningAppProvider.java:121) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.DeploymentManager.startAppProvider(DeploymentManager.java:555) at org.eclipse.jetty.deploy.DeploymentManager.doStart(DeploymentManager.java:230) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.util.component.AggregateLifeCycle.doStart(AggregateLifeCycle.java:81) at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:58) at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:96) at org.eclipse.jetty.server.Server.doStart(Server.java:277) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.xml.XmlConfiguration$1.run(XmlConfiguration.java:1266) at java.security.AccessController.doPrivileged(Native Method) at org.eclipse.jetty.xml.XmlConfiguration.main(XmlConfiguration.java:1189) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.eclipse.jetty.start.Main.invokeMain(Main.java:472) at org.eclipse.jetty.start.Main.start(Main.java:620) at org.eclipse.jetty.start.Main.main(Main.java:95) Caused by: java.lang.ClassNotFoundException: org.objectweb.asm.ClassVisitor at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:247) at org.eclipse.jetty.annotations.AnnotationConfiguration.createAnnotationParser(AnnotationConfiguration.java:154) at org.eclipse.jetty.annotations.AnnotationConfiguration.configure(AnnotationConfiguration.java:105) at org.eclipse.jetty.webapp.WebAppContext.configure(WebAppContext.java:466) at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1245) at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:706) at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:492) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:39) at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:186) at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:494) at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:141) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:145) at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:56) at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:609) at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:540) at org.eclipse.jetty.util.Scanner.scan(Scanner.java:403) at org.eclipse.jetty.util.Scanner.doStart(Scanner.java:337) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.doStart(ScanningAppProvider.java:121) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.DeploymentManager.startAppProvider(DeploymentManager.java:555) at org.eclipse.jetty.deploy.DeploymentManager.doStart(DeploymentManager.java:230) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.util.component.AggregateLifeCycle.doStart(AggregateLifeCycle.java:81) at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:58) at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:96) at org.eclipse.jetty.server.Server.doStart(Server.java:277) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.xml.XmlConfiguration$1.run(XmlConfiguration.java:1266) at java.security.AccessController.doPrivileged(Native Method) at org.eclipse.jetty.xml.XmlConfiguration.main(XmlConfiguration.java:1189) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.eclipse.jetty.start.Main.invokeMain(Main.java:472) at org.eclipse.jetty.start.Main.start(Main.java:620) at org.eclipse.jetty.start.Main.main(Main.java:95) 2013-05-18 10:19:43.855:WARN:oejd.DeploymentManager:Unable to reach node goal: started java.lang.NoClassDefFoundError: org/objectweb/asm/ClassVisitor at org.eclipse.jetty.annotations.AnnotationConfiguration.createAnnotationParser(AnnotationConfiguration.java:154) at org.eclipse.jetty.annotations.AnnotationConfiguration.configure(AnnotationConfiguration.java:105) at org.eclipse.jetty.webapp.WebAppContext.configure(WebAppContext.java:466) at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1245) at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:706) at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:492) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:39) at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:186) at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:494) at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:141) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:145) at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:56) at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:609) at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:540) at org.eclipse.jetty.util.Scanner.scan(Scanner.java:403) at org.eclipse.jetty.util.Scanner.doStart(Scanner.java:337) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.doStart(ScanningAppProvider.java:121) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.deploy.DeploymentManager.startAppProvider(DeploymentManager.java:555) at org.eclipse.jetty.deploy.DeploymentManager.doStart(DeploymentManager.java:230) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.util.component.AggregateLifeCycle.doStart(AggregateLifeCycle.java:81) at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:58) at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:96) at org.eclipse.jetty.server.Server.doStart(Server.java:277) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64) at org.eclipse.jetty.xml.XmlConfiguration$1.run(XmlConfiguration.java:1266) at java.security.AccessController.doPrivileged(Native Method) at org.eclipse.jetty.xml.XmlConfiguration.main(XmlConfiguration.java:1189) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.eclipse.jetty.start.Main.invokeMain(Main.java:472) at org.eclipse.jetty.start.Main.start(Main.java:620) at org.eclipse.jetty.start.Main.main(Main.java:95)