struts2 ognl 异常

17:02:18,510  WARN com.opensymphony.xwork2.ognl.OgnlValueStack:60 - Error setting expression 'tbscholarshiptype.scholarshipTypeCode' with value '[Ljava.lang.String;@6b7627'
ognl.OgnlException: target is null for setProperty(null, "scholarshipTypeCode", [Ljava.lang.String;@6b7627)

原因：前端页面表单 form 没有封闭。