struts启动报错Javassist library is missing

Caused by: java.lang.ExceptionInInitializerError
    at com.opensymphony.xwork2.ognl.OgnlValueStackFactory.setContainer(OgnlValueStackFactory.java:84)
    ... 64 more
Caused by: java.lang.IllegalArgumentException: Javassist library is missing in classpath! Please add missed dependency!
    at ognl.OgnlRuntime.<clinit>(OgnlRuntime.java:168)
    ... 65 more
Caused by: java.lang.ClassNotFoundException: javassist.ClassPool
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1680)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:169)
    at ognl.OgnlRuntime.<clinit>(OgnlRuntime.java:165)
    ... 65 more