String concatenation with Thymeleaf

Posted at — Jan 11, 2021
Taming Thymeleaf cover
Interested in learning more about Thymeleaf? Check out my book Taming Thymeleaf. The book combines all of my Thymeleaf knowledge into an easy to follow step-by-step guide.

This post shows the various ways that you can concatenate string values with Thymeleaf.

String concatenation

Assume for the examples a controller with these model attributes:

public class MyController {

    public String index(Model model) {
        model.addAttribute("givenName", "Layla");
        model.addAttribute("familyName", "Clapton");

Option 1

Use the + sign. Hardcoded text should be put between single quotes ('):

<h1 th:text="'Hi, ' + ${givenName} + ' ' + ${familyName}"></h1>

This renders as:

<h1>Hi, Layla Clapton</h1>

Option 2

Use the | character to perform literal substitutions:

<h1 th:text="|Hi, ${givenName} ${familyName}|"></h1>

This renders exactly the same as option 1.

Option 3

Not really recommended, but you could use different <span> tags and concatenate like that:

<h1>Hi, <span th:text="${givenName}"></span>&nbsp;<span th:text="${familyName}"></span></h1>

Note how you also need to add a non-breaking space (&nbsp;) between the spans.

Option 4

Another option is to use expression inlining.

The syntax is [[…​]]. You can put any valid th:text expression between the brackets, so both examples are valid:

<h1>Hi, [[${givenName} + ' ' + ${familyName}]]!</h1>
<h1>Hi, [[|${givenName} ${familyName}|]]!</h1>

Option 5

You can of course also just build the string in the controller itself.

public class MyController {

    public String index(Model model) {
        model.addAttribute("givenName", "Layla");
        model.addAttribute("familyName", "Clapton");
        model.addAttribute("greeting", String.format("Hi, %s %s", "Layla", "Clapton"));

With the HTML as:

<h1 th:text="${greeting}"></h1>

Join collection items

If you need to join a collection of items with a delimiter, you can use the utility methods on the #strings variable.

Suppose your controller has defined this model attribute:

model.addAttribute("names", List.of("Wim", "Layla", "John"));

Use this template:

<div th:text="${#strings.listJoin(names, ', ')}"></div>

Which will render like:

<div>Wim, Layla, John</div>

See #strings in the Thymeleaf documentation for more information.


Value substitution

We can also use the internationalization support to concatenate strings.

Suppose you have this in your file:

greeting=Hi, {0} {1}

Then you can use this in the Thymeleaf template:

<h1 th:text="#{greeting(${givenName}, ${familyName})}></h1>

This also renders as:

<h1>Hi, Layla Clapton</h1>

The advantage here is that you can translate the messages now easily by adding extra files for each language the application needs to support.

Key substitution

In some cases, you might want to output a translation depending on the value of a certain enum.

Let’s assume we have this enum:

public enum Gender {

And we have this translation file:


If we want to show the translated value, we can do this:

<span th:text="#{'Gender.' + ${user.gender}}"></span>

This assumes that the class of user has a property gender of our enum type.

URL Path concatenation

If you want to use string concatenation to build a URL, there is a bit of a different option.

Suppose the URL to edit a team is /teams/<id> where id is the long or UUID of the team. To build a link to that URL, we can do this:

<a th:href="@{/teams/{id}(id=${})}" th:text="#{}"></a>

This will render as:

<a href="/teams/1234">Edit Team</a>


Thymeleaf has a rich set of options if you need to concatenate string values for your web application.

If you want to be notified in the future about new articles, as well as other interesting things I'm working on, join my mailing list!
I send emails quite infrequently, and will never share your email address with anyone else.