Whats the difference between "${foo.bar}" and "#{foo.bar}" ?

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+1 Q:

Whats the difference between "${foo.bar}" and "#{foo.bar}" ?

I can use objects from my Java Beans within .jsp files by using the Expression Language (EL). Therefore I can get my value by typing ${foo.bar}. But I can also use #{foo.bar}.

Can anybody explain the difference or provide a link with meaningful information?

+2 A:

#{foo.bar} syntax is from the JSF expression language. Some bright spark thought it would be a good idea to use a different syntax to JSP EL (i.e. ${foo.bar}). I think some JSP containers are tolerant of this cockup, and let you use either one.

skaffman 2009-08-21 11:32:14

So I could use ${...} anytime I want and #{...} only in case of using JSF which means that #{...} has the same functionality... That really must have been a bright spark :DThanks ;)

Marcus 2009-08-21 11:36:42

JSF was a ghastly mess from day one, and they've been trying to paper over the cracks ever since.

skaffman 2009-08-21 11:38:01

Ok... but why is it a mess? I'm new to it, therefore I haven't much experience with it ;)

Marcus 2009-08-21 11:40:07

+6 A:

This is covered in the JSP 2.1 spec.

In J2EE/JEE, #{expr} is used for deferred evaluation and ${expr} for immediate evaluation. Deferred expressions (#{expr}) expressions can only be used with tag attributes that accept them. This is a J2EE convention, but other domains could impose their own meaning (e.g. if you wanted to use EL in your own templates).

McDowell 2009-08-21 12:53:51

Aha, interesting, I wasn't aware of that. +1

skaffman 2009-08-21 12:55:09

ansaurus

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Whats the difference between "${foo.bar}" and "#{foo.bar}" ?

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