This guide walks you through the process of building an application that uses a Vaadin-based UI on a Spring Data JPA based backend.
You will build a Vaadin UI for a simple JPA repository. What you will get is an application with full CRUD (Create, Read, Update, and Delete) functionality and a filtering example that uses a custom repository method.
You can follow either of two different paths:
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Starting from the
initialproject that is already in the project. -
Making a fresh start.
The differences are discussed later in this document.
You can use this pre-initialized project and click Generate to download a ZIP file. This project is configured to fit the examples in this tutorial.
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Note
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You can also fork the project from Github and open it in your IDE or other editor. |
If you want to initialize the project manually rather than use the links shown earlier, follow the steps given below:
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Navigate to https://start.spring.io. This service pulls in all the dependencies you need for an application and does most of the setup for you.
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Choose either Gradle or Maven and the language you want to use. This guide assumes that you chose Java.
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Click Dependencies and select Vaadin, Spring Data JPA and H2 Database.
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Click Generate.
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Download the resulting ZIP file, which is an archive of a web application that is configured with your choices.
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Note
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If your IDE has the Spring Initializr integration, you can complete this process from your IDE. |
This guide is a continuation from Accessing Data with JPA. The only differences are that the entity class has getters and setters and the custom search method in the repository is a bit more graceful for end users. You need not read that guide to walk through this one, but you can if you wish.
If you started with a fresh project, you need to add entity and repository objects. If you
started from the initial project, these object already exist.
The following listing (from src/main/java/com/example/crudwithvaadin/Customer.java)
defines the customer entity:
link:complete/src/main/java/com/example/crudwithvaadin/Customer.java[role=include]The following listing (from
src/main/java/com/example/crudwithvaadin/CustomerRepository.java) defines the customer
repository:
link:complete/src/main/java/com/example/crudwithvaadin/CustomerRepository.java[role=include]The following listing (from
src/main/java/com/example/crudwithvaadin/CrudWithVaadinApplication.java) shows the
application class, which creates some data for you:
link:complete/src/main/java/com/example/crudwithvaadin/CrudWithVaadinApplication.java[role=include]If you checked out the initial project, or you created your project with initializr,
you have all necessary dependencies already set up.
However, the rest of this section describes how to add Vaadin support to a fresh
Spring project. Spring’s Vaadin integration contains a Spring Boot starter dependency
collection, so you need add only the following Maven snippet (or a corresponding Gradle
configuration):
link:complete/pom.xml[role=include]The example uses a newer version of Vaadin than the default one brought in by the starter module. To use a newer version, define the Vaadin Bill of Materials (BOM) as follows:
link:complete/pom.xml[role=include]In developer mode, the dependency is enough, but When you are building for production, you need to enable your app for production builds.
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Tip
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By default, Gradle does not support BOMs, but there is a handy
plugin for that. Check out the
build.gradle build file for an example of how to accomplish the same thing.
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The main view class (called MainView in this guide) is the entry point for Vaadin’s UI
logic. In Spring Boot applications, if you annotate it with @Route, it is automatically
picked up and shown at the root of your web application. You can customize the URL where
the view is shown by giving a parameter to the @Route annotation. The following listing
(from the initial project at
src/main/java/com/example/crudwithvaadin/MainView.java) shows a simple “Hello, World”
view:
link:initial/src/main/java/com/example/crudwithvaadin/MainView.java[role=include]For a nice layout, you can use the Grid component. You can pass the list of entities
from a constructor-injected CustomerRepository to the Grid by using the setItems
method. The body of your MainView would then be as follows:
@Route
public class MainView extends VerticalLayout {
private final CustomerRepository repo;
final Grid<Customer> grid;
public MainView(CustomerRepository repo) {
this.repo = repo;
this.grid = new Grid<>(Customer.class);
add(grid);
listCustomers();
}
private void listCustomers() {
grid.setItems(repo.findAll());
}
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Tip
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If you have large tables or lots of concurrent users, you most likely do not want
to bind the whole dataset to your UI components. Although Vaadin Grid lazy loads the data from the server to the browser, the preceding approach keeps the whole list of data in the server memory. To save some memory, you could show only the topmost results by employing paging or using lazy loading, for examply using the grid.setItems(VaadinSpringDataHelpers.fromPagingRepository(repo)) method.
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Before the large data set becomes a problem to your server, it is likely to cause a
headache for your users as they try to find the relevant row to edit. You can use a
TextField component to create a filter entry. To do so, first modify the
listCustomer() method to support filtering. The following example (from the complete
project in src/main/java/com/example/crudwithvaadin/MainView.java) shows how to do so:
link:complete/src/main/java/com/example/crudwithvaadin/MainView.java[role=include]|
Note
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This is where Spring Data’s declarative queries come in handy. Writing
findByLastNameStartsWithIgnoringCase is a single line definition in the
CustomerRepository interface.
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You can hook a listener to the TextField component and plug its value into that filter
method. The ValueChangeListener is called automatically as a user types because you
define the ValueChangeMode.LAZY on the filter text field. The following example shows
how to set up such a listener:
TextField filter = new TextField();
filter.setPlaceholder("Filter by last name");
filter.setValueChangeMode(ValueChangeMode.LAZY);
filter.addValueChangeListener(e -> listCustomers(e.getValue()));
add(filter, grid);As Vaadin UIs are plain Java code, you can write re-usable code from the beginning. To do
so, define an editor component for your Customer entity. You can make it be a
Spring-managed bean so that you can directly inject the CustomerRepository into the
editor and tackle the Create, Update, and Delete parts or your CRUD functionality. The
following example (from src/main/java/com/example/crudwithvaadin/CustomerEditor.java)
shows how to do so:
link:complete/src/main/java/com/example/crudwithvaadin/CustomerEditor.java[role=include]In a larger application, you could then use this editor component in multiple places. Also note that, in large applications, you might want to apply some common patterns (such as MVP) to structure your UI code.
In the previous steps, you have already seen some basics of component-based programming.
By using a Button and adding a selection listener to Grid, you can fully integrate
your editor into the main view. The following listing (from
src/main/java/com/example/crudwithvaadin/MainView.java) shows the final version of the
MainView class:
link:complete/src/main/java/com/example/crudwithvaadin/MainView.java[role=include]You can see your Vaadin application running at http://localhost:8080
Congratulations! You have written a full-featured CRUD UI application by using Spring Data JPA for persistence. And you did it without exposing any REST services or having to write a single line of JavaScript or HTML.