jbpm4.4在jetty6下的ClassCastException

mengz

在pom.xml中加入jBPM4.4的支持, 用jetty6跑的时候发现, 在jsp中只要使用EL就会报:
java.lang.ClassCastException: de.odysseus.el.ExpressionFactoryImpl cannot be cast to javax.el.ExpressionFactory.
 
后来在jbpm-4.4.pom中发现这样一段话:
The juel engine is the library from scripting.java.sun.com that exposes juel as a jsr233 scripting engine. It's not part of the juel distribution. For some reason i don't recall, we uploaded it as an juel-engine artifact in the group juel. And more problematic, used the juel version (2.1.0) for it. That is not intuitive.

怀疑是这个问题,于是在jbpm-pvm下排除:
<dependency>
   <groupId>org.jbpm.jbpm4</groupId>
   <artifactId>jbpm-pvm</artifactId>
   <version>4.4</version>
   <exclusions>
    <exclusion>
     <groupId>juel</groupId>
     <artifactId>juel-engine</artifactId>
    </exclusion>
    <exclusion>
     <groupId>juel</groupId>
     <artifactId>juel-api</artifactId>
    </exclusion>
    <exclusion>
     <groupId>juel</groupId>
     <artifactId>juel-impl</artifactId>
    </exclusion>
   </exclusions>
  </dependency>
 
问题解决.