求解一个异常:java.lang.ClassNotFoundException: javax.el.FunctionMapper
异常信息如下:

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'processEngine' defined in class path resource [applicationContext.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.jbpm.api.ProcessEngine org.jbpm.pvm.internal.processengine.SpringHelper.createProcessEngine()] threw exception; nested exception is java.lang.NoClassDefFoundError: javax/el/FunctionMapper
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:581)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:983)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:879)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:580)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at com.beyondsoft.test.FirstTest.main(FirstTest.java:15)
Caused by: org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.jbpm.api.ProcessEngine org.jbpm.pvm.internal.processengine.SpringHelper.createProcessEngine()] threw exception; nested exception is java.lang.NoClassDefFoundError: javax/el/FunctionMapper
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:157)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:570)
... 14 more
Caused by: java.lang.NoClassDefFoundError: javax/el/FunctionMapper
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.j