No result type specified for result named 'success', perhaps the parent package does not specify the result type...

Caused by: No result type specified for result named 'success', perhaps the parent package does not specify the result type? - result - file:/E:/anzhuang/tomcat7/apache-tomcat-7.0.70-windows-x64/apache-tomcat-7.0.70/webapps/struts2/WEB-INF/classes/cn/itcast/context/struts_context.xml:13:28
    at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.buildResults(XmlConfigurationProvider.java:716)
    at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:439)
    ... 27 more

出现这个错误的原因是我的package忘了继承struts-default包了。