SSH错误之--Error getting property descriptor: null at com.opensymphony.xwork2.ognl.accessor.XWorkCollectionPropertyAccessor.getProperty

Error setting expression 'users.makeNew[0].username' with value '[Ljava.lang.String;@5ab5b91' ognl.OgnlException: Error getting property descriptor: null at com.opensymphony.xwork2.ognl.accessor.XWorkCollectionPropertyAccessor.getProperty法

根据http://javaligang.blog.51cto.com/5026500/874468的说法，暂时不知道怎么处理好。