Access map with integer key from JSF EL

Question

In a backing bean I have defined a Map<Integer,String> property. When trying to access the map from EL inside an xhtml-file, I get nothing back.

<h:outputLabel value="#{bean.myMap[0]}">

does not return the value for key 0. With a String key it works.

It works with a List<String>, but I want the Map to have some kind of sparse array (not all indexes have values)

@RongNK which component of omnifaces would be applicable here? — Luiggi Mendoza, Jun 17 '13 at 08:33
possible duplicate of [JSTL access a map value by key](http://stackoverflow.com/questions/924451/jstl-access-a-map-value-by-key) — Luiggi Mendoza, Jun 17 '13 at 08:35
@LuiggiMendoza Ok, didn't know that EL in JSF is the same as JSTL. — Björn Landmesser, Jun 17 '13 at 09:08
@BjörnMilcke EL and JSTL are not the same.EL is declared by `${}` and `#{}` while JSTL is a tag library that helps working with EL. More info in their respective stackoverflow wiki pages: [EL](http://stackoverflow.com/tags/el/info) and [JSTL](http://stackoverflow.com/tags/jstl/info). Also, refer to [JSTL in JSF2 Facelets… makes sense?](http://stackoverflow.com/q/3342984/1065197) — Luiggi Mendoza, Jun 17 '13 at 09:56
@LuiggiMendoza So, then I assume this question is no duplicate to the JSTL question, although the answers are the same. — Björn Landmesser, Jun 17 '13 at 12:58
It's a duplicate question because they face the same problem and same answer. — Luiggi Mendoza, Jun 17 '13 at 14:10

AllTooSir · Accepted Answer · 2013-06-17T08:10:51.517

8

EL interprets your literal number 0 as long type. Try a Map<Long,String> instead of Map<Integer,String>.

This is what you are supposedly doing :

myMap.put(Integer.valueOf(0), "SomeValue");

This is what EL does to get back the value :

String value = myMap.get(Long.valueOf(0));

edited Jun 17 '13 at 08:10

answered Jun 17 '13 at 08:05

AllTooSir

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score 3 · Answer 2 · answered Apr 16 '15 at 07:01

I had the same problem and found this when I was googling for a solution. Changing the map wasn't really an option for me, since it was auto-generated code, so here's what I ended up doing.

I created a managed bean:

package my.bean.tool;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ApplicationScoped;

@ManagedBean
@ApplicationScoped
public class Caster {

    public Caster() {
    }

    public int toInt(long l) {
        return (int) l;
    }
}

Then I simply did what in your case would have been:

<h:outputLabel value="#{bean.myMap.get(caster.toInt(0))}">

Access map with integer key from JSF EL

2 Answers2