JSP表达式语言错误行为?

我有一个JSP,它使用这样的bean:

<jsp:useBean id="helper"
             type="com.example.SomeType"
             scope="request"/>

helper

<!-- This works properly, but could fail silently if the bean name is incorrect. -->
<div><p>Here's some stuff: ${helper.stuff}</div>

,我注意到了

<!-- Wrong name! "foo" should be "helper" but no error is observed (other than missing ouput)! -->
<div><p>Here's some stuff: ${foo.stuff}</div>

:

<!-- Wrong name, but an error is raised. -->
<div><p>Here's some stuff: <jsp:getProperty name="foo" property="stuff"/></div>

在这种情况下,日志会记录此条目:

SEVERE: requestURI: /some.jsp servletName: jsp statusCode: 500
org.apache.jasper.JasperException: Attempted a bean operation on a null object.

jsp:getProperty

<!-- Works properly, protects me from an incorrect name, but is more verbose than EL. -->
<div><p>Here's some stuff: <jsp:getProperty name="helper" property="stuff"/></div>