org.hibernate.MappingException:Unknown entity:java.util.ArrayList

1、错误描述

[CQ] ERROR [http-apr-8888-exec-3] com.opensymphony.xwork2.util.logging.commons.CommonsLogger.error (38)|Exception occurred during processing request:Unknown entity:java.util.ArrayList

org.hibernate.MappingException:Unknown entity:java.util.ArrayList

2、错误描述

     方法中利用Map

     private Map<String,String> findData(List<User> list,String userId);

     在Action中调用这个方法时，只传一个userId参数，没有给list赋值

3、解决办法

     去掉没有用到的list