Caused by: javax.el.PropertyNotFoundException: Property [userName] not found on type [java.lang.String]

Caused by: javax.el.PropertyNotFoundException: Property [userName] not found on type [java.lang.String]
at javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:260)
at javax.el.BeanELResolver$BeanProperties.access$300(BeanELResolver.java:212)
at javax.el.BeanELResolver.property(BeanELResolver.java:347)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:92)
at org.apache.jasper.el.JasperELResolver.getValue(JasperELResolver.java:110)
at org.apache.el.parser.AstValue.getValue(AstValue.java:169)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:190)
at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:944)
at org.apache.jsp.main_jsp._jspService(main_jsp.java:120)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
... 61 more

意思就是沒有找到el表达式中的属性，检查一下是不是属性名写错了