Master Mustache Templates in Spring Boot 3: From Basics to Real‑World Examples

1. Introduction

In this article we introduce Mustache, a logic‑less template language that allows variables and simple control structures to be embedded in web pages or other text documents.

Purpose of Mustache

Mustache’s main goal is to separate the presentation layer from business logic in web applications, offering a simple and intuitive way to create dynamic content by embedding variables and basic control structures in templates.

Mustache Syntax

Mustache syntax consists of tags wrapped in double curly braces ({{ }}). These tags can represent variables, sections, or inverted sections.

Variables: {{ variableName }} – the variable is replaced with its value during rendering.

Sections: {{# sectionName }} ... {{/ sectionName }} – renders the block only when the value is truthy.

Inverted Sections: {{^ sectionName }} ... {{/ sectionName }} – renders the block only when the value is falsy.

Partials: {{> partialName }} – reusable templates that can be included in other templates.

Example in Spring Boot

Define Data Model

<code>public class User {
  private String name;
  private int age;
  // getters, setters
}</code>

Define Controller Interface

<code>@Controller
public class UserController {

  @GetMapping("/user")
  public String getUser(Model model) {
    User user = new User("John Doe", 30);
    model.addAttribute("user", user);
    // return the template name
    return "user";
  }
}</code>

Define user.mustache Template

<code>&lt;html&gt;
&lt;head&gt;&lt;title&gt;User Information&lt;/title&gt;&lt;/head&gt;
&lt;body&gt;
  &lt;h1&gt;User Information&lt;/h1&gt;
  &lt;p&gt;Name: {{ user.name }}&lt;/p&gt;
  &lt;p&gt;Age: {{ user.age }}&lt;/p&gt;
&lt;/body&gt;
&lt;/html&gt;</code>

The above simple usage shows how Mustache keeps templates free of complex logic, making them easier to read and maintain.

2. Practical Cases

2.1 Environment

Spring Boot version 3.4.2.

2.2 Basic Syntax Usage

All syntax elements are demonstrated in the previous sections.

2.3 Collection Data

To iterate over a list or array, use the section syntax {{# users }} … {{/ users }} . Example:

<code>&lt;!DOCTYPE html&gt;
&lt;html lang="en"&gt;
&lt;head&gt;&lt;meta charset="UTF-8"&gt;&lt;title&gt;User List&lt;/title&gt;&lt;/head&gt;
&lt;body&gt;
  &lt;h1&gt;User List&lt;/h1&gt;
  &lt;ul&gt;
    {{# users }}
      &lt;li&gt;Name: {{ name }}, Age: {{ age }}&lt;/li&gt;
    {{/ users }}
  &lt;/ul&gt;
&lt;/body&gt;
&lt;/html&gt;</code>

Controller to provide the list:

<code>@GetMapping("/users")
public String getUsers(Model model) {
  List<User> userList = Arrays.asList(
    new User("Pack", 33),
    new User("XP", 25),
    new User("张三", 35)
  );
  model.addAttribute("users", userList);
  return "users";
}</code>

2.4 Form Handling

Form submission can be bound to a model object and processed by a controller:

<code>&lt;!DOCTYPE html&gt;
&lt;html lang="en"&gt;
&lt;head&gt;&lt;meta charset="UTF-8"&gt;&lt;title&gt;Form&lt;/title&gt;&lt;/head&gt;
&lt;body&gt;
  &lt;h1&gt;Form&lt;/h1&gt;
  &lt;form action="/form" method="post"&gt;
    &lt;label for="name"&gt;Name:&lt;/label&gt; &lt;input type="text" id="name" name="name"&gt;&lt;br&gt;
    &lt;label for="age"&gt;Age:&lt;/label&gt; &lt;input type="number" id="age" name="age"&gt;&lt;br&gt;
    &lt;input type="submit" value="Submit"&gt;
  &lt;/form&gt;
&lt;/body&gt;
&lt;/html&gt;</code>

<code>@GetMapping("/view")
public String view() {
  return "form";
}

@PostMapping("/form")
public String submit(User user) {
  System.err.printf("Received data: %s%n", user);
  return "redirect:/view";
}</code>

When the form is submitted, the console prints the received User object.

2.5 Partial Template

A partial can be defined as:

<code>&lt;h3&gt;This page is supported by Pack&lt;/h3&gt;</code>

and included in other templates with {{> footer }} .

Overall, the article demonstrates how to integrate Mustache into a Spring Boot project, covering variable interpolation, sections, inverted sections, partials, collection rendering, and form processing, providing a complete reference for building dynamic web pages with minimal logic in the view layer.