關於Bad version number in .class file的問題

錯誤提示：

javax.servlet.ServletException: java.lang.UnsupportedClassVersionError: Bad version number in .class file
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:268)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
	org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1069)
	org.apache.struts.tiles.TilesRequestProcessor.doForward(TilesRequestProcessor.java:274)
	org.apache.struts.tiles.TilesRequestProcessor.processTilesDefinition(TilesRequestProcessor.java:254)
	org.apache.struts.tiles.TilesRequestProcessor.processForwardConfig(TilesRequestProcessor.java:309)
	org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:279)
	org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
	org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
	com.sfit.futuresmargin.web.base.common.EncodingFilter.doFilter(EncodingFilter.java:28)

解決方案：

1. 查看web工程引用的java類庫版本和eclipse java編譯器版本是否一致

2.  查看應用中間件Tomcat使用的jdk版本（查看系統環境變量JAVA_HOME的值）

必須三者保持一致