Struts常见异常解答：There is no Action mapped for namespace / and action name . - [unknown location]

There is no Action mapped for namespace / and action name . - [unknown location]    at com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:189)    at org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:61)    at org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:39)    at com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:58)    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:475)    at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)    at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)    at java.lang.Thread.run(Thread.java:722)

这是我在用struts+mybatis开发项目是遇到的异常，这也是比较常见的Action异常。
我解决的几种路子
1. 首先检查你的struts.xml配置文件是否在src根路径下.
2. 配置文件中的action路径是否正确，包括namespace.
3. mybatis-config.xml配置文件是否在src的根路径下。
4. mybatis-config.xml配置文件中的resultMap的属性名和列名是否对应无误，列名要大写.
5. 其次检查你的数据库是否开启，表是否能打开.

以上是我在做项目时出的错的总结。。。如有什么问题可留言。。