Struts2 s:select 如何加载List<Object[]> 和Map<String,String>

map的时候这么写的
/s:select

报错
org.apache.jasper.JasperException: tag 'select', field 'list', name 'ptYxsbgkxx.ptYxsbjbqk.ptYxsbjbqk.yxsh': The requested list key 'sjyxshs' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]

测试Action中 sjyxshs是有值的。不知道哪里出了问题。求救啊