struts2空指针——spring的class没有获取到 web.xml中listener没有加listener-class标签

Struts Problem Report

Struts has detected an unhandled exception:

Messages:
File:	cn/web/action/CustomerAction.java
Line number:	33

Stacktraces

java.lang.NullPointerException

    cn.web.action.CustomerAction.add(CustomerAction.java:33)

    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

    java.lang.reflect.Method.invoke(Method.java:497)

    ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:870)

    ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293)

    ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)

    com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)

    com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)

    ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369)

    ognl.ASTMethod.getValueBody(ASTMethod.java:90)

    ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)

    ognl.SimpleNode.getValue(SimpleNode.java:258)

报错是报在ac.getBean("")处，即ac为null