How To Iterate HashMap in FreeMarker (FTL)

In this short article we will see how to iterate an HashMap in FreeMarker template. Consider below code which is normally used to iterate a List in FTL.

// Java
List<String> cityList = new ArrayList<String>();
cityList.add("Washington DC");
cityList.add("Delhi");
cityList.add("Berlin");
cityList.add("Paris");
cityList.add("Rome");
request.setAttribute("cityList", cityList);

// FTL template
<#list cityList as city>
    <b> ${city} </b>
</#list>
Code language: Java (java)

Output:

Washington DC
Delhi
Berlin
Paris
Rome

Here in above code, we created a List object and passed it to FTL page. In FTL we used <#list> to iterate and print its values.

Problem Statement

So here’s the problem statement. I have an Hashmap which I want to iterate and display in my FTL (FreeMarker) template. Consider following code in Java.
So how to iterate this Hashmap in FTL and display its values?

//Java
Map<String, String> countryCapitalList = new HashMap<String, String>();
countryCapitalList.put("United States", "Washington DC");
countryCapitalList.put("India", "Delhi");
countryCapitalList.put("Germany", "Berlin");
countryCapitalList.put("France", "Paris");
countryCapitalList.put("Italy", "Rome");
request.setAttribute("capitalList", countryCapitalList);
Code language: Java (java)

Solution

Well, the above hashmap can be iterated in FTL using following code:

<#list capitalList?keys as key>
    ${key} = ${capitalList[key]}
</#list>
Code language: Java (java)

Output:

United States = Washington DC
India = Delhi
Germany = Berlin
France = Paris
Italy = Rome

In above code, we used ?keys attribute to get the keySet of HashMap. This key set is iterated and corresponding value is fetched by user.get(key) method.
Note: One thing that’s worth noting here is that the sequence in which the values are printing may be different then the actual sequence in which values are added in hashmap. This is because, hashmap doesn’t preserve order or values. If you want to preserve the sequence of keys use LinkedHashMap.

Hope this helps.