在JSP页面内进行调试? [英] Debugging inside a JSP page?

问题描述

我正在使用Java 1.6，Spring 3.4，Spring Webflow 2.3.2和Tomcat7.我正在尝试调试使用EL表达式的JSP页面，例如:

I'm using Java 1.6, Spring 3.4, Spring Webflow 2.3.2 and Tomcat 7. I'm trying to debug a JSP page which uses EL expressions like:

<c:if test="${myObject.myThing == SomeClass.ENUMVALUE.myvalue}"  >

myObject对象作为Webflow模型对象传递.我在此行上设置了一个断点，可以到达它并中断它，但是我尝试观察"或评估"的任何操作都会给我一条错误消息.我得到

The myObject object is passed in as the Webflow model object. I have a breakpoint set on this line and I am able to reach it and break on it, but anything I try to "watch" or "evaluate" gives me an error message. I get either

${myObject.myThing == SomeClass.ENUMVALUE.myvalue}:  Invalid Expression

myObject.myThing:  Type is unknown for 'myObject'

(MyCorrectType) myObject:  Cannot find local variable 'myObject'

如何找到该模型对象?到达JSP页面时包含的内容是什么?

How the heck can I find this model object? What is it contained in by the time it reaches the JSP page?

推荐答案

答案是，它将位于org.apache.catalina.connector.Request对象中(在我的特定情况下，它被埋在包装对象的深处.)

The answer turned out to be that it will be in the org.apache.catalina.connector.Request object (In my particular case, it was buried several levels deep inside wrapper objects.)

如果您正在使用调试器，例如Intellij中的调试器(我使用的调试器)，则可以通过对表达式request.getAttribute("attributeName")求值来获取单个属性的值(例如Webflow模型对象).请注意，这可能会返回Java Object类型，并且您可能必须将其强制转换为正确的类型.

If you are using a debugger, like the one in Intellij (which I use), you can get the value of an individual attribute (like the Webflow model object) by evaluating the expression request.getAttribute("attributeName"). Note that this may return a Java Object type, and you may have to cast it to the correct type.

例如，对于我来说，我可以使用以下表达式找到所需的值:

For example, in my case, I was able to find the value of the value I wanted using this expression:

((MyObject)(request.getAttribute("myObject"))).getMyThing()

我希望这对某人有帮助.

I hope this helps somebody.

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