运行Tomcat + Spring + Maven项目(Eclipse)时出现NoClassDefFoundError

Question

我得到的是:

java.lang.NoClassDefFoundError: com/mongodb/DB
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2427)
at java.lang.Class.getDeclaredMethods(Class.java:1791)
at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:446)
at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:430)
at org.springframework.util.ReflectionUtils.getAllDeclaredMethods(ReflectionUtils.java:475)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryMethod(AbstractAutowireCapableBeanFactory.java:634)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:573)
at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1319)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:315)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:394)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:594)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:407)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:442)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:458)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:339)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:306)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:127)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1173)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:993)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4420)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4733)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
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:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

这个类在maven jar里面(来自M2存储库).我将Maven Dependencies添加到DeploymentAssembly(在我做之前我得到了:java.lang.ClassNotFoundException:org.springframework.web.filter.CharacterEncodingFilter).我使用m2e插件并将我的项目配置为Maven项目.我的应用程序部署到标准位置/.metadata/.plugins/.../tmp0.在WEB-INF/lib里面我有所有必要的罐子.项目编译没有错误.我该怎么办？

一个准解决方案是向Tomcat lib目录添加必要的库,但我不想这样做.我想强制Tomcat使用项目库.

Answer 1

我在尝试运行mcv-ajax和mvc-basic样本时遇到了类似的问题,这些样本随Spring 3一起发布(两者都可以在https://src.springframework.org/svn/spring-samples上找到 - 需要一个SVN客户端来下载他们,比如TortoiseSVN).

我在Tomcat6启动日志中收到此ClassNotFoundException.

SEVERE: Exception starting filter characterEncodingFilter java.lang.ClassNotFoundException: org.springframework.web.filter.CharacterEncodingFilter
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1680)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
    at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:269)
    at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4071)
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:4725)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
    at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
    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:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Feb 17, 2012 10:36:18 AM org.apache.catalina.core.StandardContext start
SEVERE: Error filterStart
Feb 17, 2012 10:36:18 AM org.apache.catalina.core.StandardContext start
SEVERE: Context [/mvc-basic] startup failed due to previous errors

我可以运行Maven Clean和Maven Install目标,没有错误,并且项目没有任何类路径错误.我还按照Maven Integration for Eclipse Extras软件包安装了eclipse Maven Integration for WTP,如此处所示,但仍然没有运气......

在我的案例中,问题可以在Eclipse 的Markers选项卡中看到,作为一个警告(黄色感叹号),带有Classpath Dependency验证器Message的描述, 并且不会导出类路径条目org.eclipse.maven2_classpath.container的实际问题或发表.可能会导致运行时ClassNotFoundExceptions.

解决这个问题

1. 右键单击问题描述,然后选择快速修复.
2. 选择将关联的原始类路径条目标记为发布/导出依赖项
3. 单击"完成"
4. 做一个maven-clean和maven-install
5. 右键单击项目,选择在服务器上运行.选择要运行的Tomcat服务器,您应该看到初始页面.

结论上面描述的步骤对我来说非常有效,可以让我的项目在我的Eclispe开发环境中成功运行.请试一试,看看它是否适合您.

另一种似乎也起作用的解决方案是

1. 从eclipse中删除项目,包括工作区中的所有相关文件.(也从工作区中删除项目目录)
2. 再次从SVN检查项目到工作区
3. 在eclipse中导入新项目,但选择Maven\Existing Maven Project
4. 从磁盘中选择项目并导入.

亲切的问候,

ta6hbe