Request Parameter -Regarding

[vinod balaji]

mock exam Question:
${request.noise} #1
${param.noise} #2
${requestScope.noise}#3
What will happen when the page is compiled and executed with the query string

index.jsp?noise=moo

What is the Output and which one will work.

[Gowher Naik]

output is #1 moo #2 #3
${param.noise} will execute.

[vinod balaji]

Ok thanks

[Firas Zuriekat]

 
${requestScope.noise}#3
What will happen when the page is compiled and executed with the query string
 
index.jsp?noise=moo

"noise" in this case is a request attribute and not a parameter. Therefore, the output of ${requestScope.noise} is nothing. This is because "noise" as a parameter is not defined.

Please let me know if I am correct?

[Abhijeet Mahule]

Hi Firas,
The line: index.jsp?noise=moo
indicates that index.jsp is being invoked with a parameter whose name is "noise" and value is "moo".
Now this parameter value can be retrieved in the index.jsp page by using the EL expression ${param.noise}. Note that "param" is the implicit EL variable that is used to retieve the value of parameter being sent to the jsp.

${requestScope.noise} refers to the value of attribute object named "noise" that is added to the request scope(request.setAttribute(String name,Object obj)) and is retrievable using the implicit EL variable "requestScope".

The expression ${request.noise} is invalid since there is no implicit EL variable named "request".

Hence the answer is: #1 moo #2 #3
Note that "noise" is a parameter not a request attribute.

Hope this is clear


Stay connected, Remain beautiful,
Abhijeet
SCJP 1.4, SCWCD 1.4

[ December 18, 2006: Message edited by: Abhijeet Mahule ]
[ December 18, 2006: Message edited by: Abhijeet Mahule ]

[Firas Zuriekat]

yes, this clears many things. If one could remember that EL almost never throws an Exception or Error (it's very forgiving), then the output here will be nothing when ${request.noise} is used (request doesn't exist in EL).

So that's why we get this result even when using this non-existent "request".



EL is cool
[ December 18, 2006: Message edited by: Firas Zuriekat ]

[Niranjan Deshpande]

good revision for me