jbpm4.4在jetty6下的ClassCastException

最新推荐文章于 2025-12-12 22:03:41 发布

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本文介绍了解决JBPM 4.4与JUEL在使用EL表达式时出现的ClassCastException错误的方法。通过在pom.xml文件中排除特定的JUEL依赖项，可以避免与JBPM中的EL实现冲突。

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>