如何在jsp中的Javascript中访问映射键，值（java.util.Map）？

Question

Problem is I'm not able to get the map key and its values (which is again a Java ArrayList) in Javascript function

My code is as below:

function myset() {
    var mymap="${range}";//range is a java map which is accessible here

// Here I need to display the mymap key and its value (which is an arraylist)
}

<select id="bn" name="bn" onchange="myset()">
</select>

range is a Java map as follows:

List<String> l=new ArrayList<String>();
l.add("123");
l.add("456");
l.add("789");
List<String> ls=new ArrayList<String>();
l.add("222");
l.add("456");
l.add("333");
Map<String,List<String>> m=new HashMap<String,List<String>>();
m.put("123", l);
m.put("456", ls);

Can you please tell me how to display the map key and its concerned arraylist in the above Javascript function?

Answer 1

var mymap="${range}";//range is a java map which is accessible here

Doing this, you are just doing

var mymap="#{range.toString()}" 

(or, if you have defined a converter, the value returned by it).

You will need to iterate in your Java code to create the JS code that will populate the map.

Think that JS and Java work in both completely separated VM (most likely in different computers), so you can not just pass a reference to Java and expect it to "work" in JS. You have to copy all the data.