1. Overview
In this tutorial, we’ll go over an example application that renders a single page with a Vue.js frontend, while using Spring Boot as a backend.
We’ll also utilize Thymeleaf to pass information to the template.
2. Spring Boot Setup
The application pom.xml uses the spring-boot-starter-thymeleaf dependency for template rendering along with the usual spring-boot-starter-web:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
<version>2.0.3.RELEASE</version>
</dependency>
Thymeleaf by default looks for view templates at templates/, we’ll add an empty index.html to src/main/resources/templates/index.html. We’ll update its contents in the next section.
Finally, our Spring Boot controller will be in src/main/java:
@Controller
public class MainController {
@GetMapping("/")
public String index(Model model) {
model.addAttribute("eventName", "FIFA 2018");
return "index";
}
}
This controller renders a single template with data passed to the view via the Spring Web Model object using model.addAttribute.
Let’s run the application using:
mvn spring-boot:run
Browse to http://localhost:8080 to see the index page. It’ll be empty at this point, of course.
Our goal is to make the page print out something like this:
Name of Event: FIFA 2018 Lionel Messi Argentina's superstar Christiano Ronaldo Portugal top-ranked player
3. Rendering Data Using a Vue.Js Component
3.1. Basic Setup of Template
In the template, let’s load Vue.js and Bootstrap (optional) to render the User Interface:
// in head tag <!-- Include Bootstrap --> // other markup // at end of body tag <script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.js"> </script> <script src="https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.21.1/babel.min.js"> </script>
Here we load Vue.js from a CDN, but you can host it too if that’s preferable.
We load Babel in-browser so that we can write some ES6-compliant code in the page without having to run transpilation steps.
In a real-world application, you’ll likely use a build process using a tool such as Webpack and Babel transpiler, instead of using in-browser Babel.
Now let’s save the page and restart using the mvn spring-boot:run command. We refresh the browser to see our updates; nothing interesting yet.
Next, let’s set up an empty div element to which we’ll attach our User Interface:
<div id="contents"></div>
Next, we set up a Vue application on the page:
<script type="text/babel">
var app = new Vue({
el: '#contents'
});
</script>
What just happened? This code creates a Vue application on the page. We attach it to the element with CSS selector #contents.
That refers to the empty div element on the page. The application is now set up to use Vue.js!
3.2. Displaying Data in the Template
Next, let’s create a header which shows the ‘eventName‘ attribute we passed from Spring controller, and render it using Thymeleaf’s features:
<div class="lead">
<strong>Name of Event:</strong>
<span th:text="${eventName}"></span>
</div>
Now let’s attach a ‘data’ attribute to the Vue application to hold our array of player data, which is a simple JSON array.
Our Vue app now looks like this:
<script type="text/babel">
var app = new Vue({
el: '#contents',
data: {
players: [
{ id: "1",
name: "Lionel Messi",
description: "Argentina's superstar" },
{ id: "2",
name: "Christiano Ronaldo",
description: "World #1-ranked player from Portugal" }
]
}
});
</script>
Now Vue.js knows about a data attribute called players.
3.3. Rendering Data with a Vue.js Component
Next, let’s create a Vue.js component named player-card which renders just one player. Remember to register this component before creating the Vue app.
Otherwise, Vue won’t find it:
Vue.component('player-card', {
props: ['player'],
template: `<div class="card">
<div class="card-body">
<h6 class="card-title">
{{ player.name }}
</h6>
<p class="card-text">
<div>
{{ player.description }}
</div>
</p>
</div>
</div>`
});
Finally, let’s loop over the set of players in the app object and render a player-card component for each player:
<ul>
<li style="list-style-type:none" v-for="player in players">
<player-card
v-bind:player="player"
v-bind:key="player.id">
</player-card>
</li>
</ul>
The logic here is the Vue directive called v-for, which will loop over each player in the players data attribute and render a player-card for each player entry inside a <li> element.
v-bind:player means that the player-card component will be given a property called player whose value will be the player loop variable currently being worked with. v-bind:key is required to make each <li> element unique.
Generally, player.id is a good choice since it is already unique.
Now if you reload this page, observe the generated HTML markup in devtools, and it will look similar to this:
<ul>
<li style="list-style-type: none;">
<div class="card">
// contents
</div>
</li>
<li style="list-style-type: none;">
<div class="card">
// contents
</div>
</li>
</ul>
A workflow improvement note: it’ll quickly become cumbersome to have to restart the application and refresh the browser each time you make a change to the code.
Therefore, to make life easier, please refer to this article on how to use Spring Boot devtools and automatic restart.
4. Conclusion
In this quick article, we went over how to set up a web application using Spring Boot for backend and Vue.js for the frontend. This recipe can form the basis for more powerful and scalable applications, and this is just a starting point for most such applications.
As usual, code samples can be found over on GitHub.
