您需要更改EL才能在valueStack中找到操作变量.

You need to change EL to find your action variable in the valueStack.

<c:out value="${pageNumber}"/> 

请注意，由于Struts请求包装程序，EL表达式应有权访问valueStack变量.请参见我们如何在框架中使用JSTL .

Note, that EL expressions should have access to valueStack variables due to Struts request wrapper. See How we use JSTL with the framework.