How do you reference an constants with EL on a JSP page?
I have an interface Addresses with a constant named URL. I know I can reference it with a scriplet by going: , but how do I do this using EL?
This is not possible using standard EL in its current 2.2 release. There are however several ways to achieve the requirement:
Put them in a Map which you put in the application scope. In EL, map values are accessible the usual Javabean way by ${map.key} or ${map['key.with.dots']}.
Use of the Unstandard taglib (maven2 repo here):
This way they are accessible the usual Javabean way by ${constants}.
Use Javaranch's CCC as desribed somewhere at the bottom of this article.
This way they are accessible the usual Javabean way by ${constants} as well.
If you're using JSF2, then you could use of OmniFaces.
This way they are accessible the usual Javabean way by #{YourConstants} as well.
Create a wrapper class which returns them through Javabean-style getter methods.
Create a custom EL resolver which first scans the presence of a constant and if absent, then delegate to the default resolver, otherwise returns the constant value instead.