报错原因是缺少jar包ognl-3.0.jar
另，搭建struts2至少需要：
commons-io-1.3.2.jar
commons-logging-1.0.4.jar
freemarker-2.3.16.jar
javassist-3.7.ga.jar
ognl-3.0.jar
struts2-core-2.2.1.jar
xwork-core-2.2.1.jar
报错原因是缺少jar包ognl-3.0.jar
另，搭建struts2至少需要：
commons-io-1.3.2.jar
commons-logging-1.0.4.jar
freemarker-2.3.16.jar
javassist-3.7.ga.jar
ognl-3.0.jar
struts2-core-2.2.1.jar
xwork-core-2.2.1.jar