No action instance for path /leftTreeMenu could be created-优快云博客

本文针对Struts框架中出现的NullPointerException错误进行了详细分析，并提供了解决方案。通过在struct-config.xml文件中添加特定配置，成功解决了No action instance for path/leftTreeMenu could be created的问题。

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报错信息：

14:12:12,484 ERROR RequestProcessor:284 - No action instance for path /leftTreeMenu could be created
java.lang.NullPointerException
at sun.jkernel.DownloadManager.getBootClassPathEntryForClass(DownloadManager.java:891)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:293)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1255)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1189)
at org.apache.struts.util.RequestUtils.applicationClass(RequestUtils.java:117)
at org.apache.struts.util.RequestUtils.applicationInstance(RequestUtils.java:143)
at org.apache.struts.action.RequestProcessor.processActionCreate(RequestProcessor.java:280)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:218)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

解决办法：

在struct-config.xml中 </action-mappings>标签后面加这么一句：