Vaadin Hello World Web Application with Maven

In this example, we will learn to create vaadin hello world application using maven, and then we will run deploy the application in built-in jetty server.

Create vaadin project using maven archetype

Use below maven command in your workspace to create simplest vaadin web application.

$ mvn archetype:generate 
	-DarchetypeGroupId=com.vaadin 
	-DarchetypeArtifactId=vaadin-archetype-application 
	-DarchetypeVersion=LATEST 
	-DgroupId=com.howtodoinjava.vaadin.demo 
	-DartifactId=VaadinExample 
	-Dversion=1.0 
	-Dpackaging=war

Please update the -DgroupId and -DartifactId as per your need.

Generated project structure

Now import the generated project into your IDE (in my case, it’s eclipse) as existing maven project.

The generated project contains standard folder structure for any maven web application.

Generated files

Along with folder structure, we get these generated files along with vaadin hello world project.

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd;
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.howtodoinjava.vaadin.demo</groupId>
	<artifactId>VaadinExample</artifactId>
	<packaging>war</packaging>
	<version>1.0</version>
	<name>VaadinExample</name>

	<prerequisites>
		<maven>3</maven>
	</prerequisites>

	<properties>
		<vaadin.version>7.7.0</vaadin.version>
		<vaadin.plugin.version>7.7.0</vaadin.plugin.version>
		<jetty.plugin.version>9.3.9.v20160517</jetty.plugin.version>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<maven.compiler.source>1.8</maven.compiler.source>
		<maven.compiler.target>1.8</maven.compiler.target>
		<!-- If there are no local customisations, this can also be "fetch" or "cdn" -->
		<vaadin.widgetset.mode>local</vaadin.widgetset.mode>
	</properties>

	<repositories>
		<repository>
			<id>vaadin-addons</id>
			<url>http://maven.vaadin.com/vaadin-addons</url>
		</repository>
		<repository>
			<id>vaadin-snapshots</id>
			<url>https://oss.sonatype.org/content/repositories/vaadin-snapshots/</url>
			<releases>
				<enabled>false</enabled>
			</releases>
			<snapshots>
				<enabled>true</enabled>
			</snapshots>
		</repository>
	</repositories>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>com.vaadin</groupId>
				<artifactId>vaadin-bom</artifactId>
				<version>${vaadin.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<dependencies>
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>3.0.1</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>com.vaadin</groupId>
			<artifactId>vaadin-server</artifactId>
		</dependency>
		<dependency>
			<groupId>com.vaadin</groupId>
			<artifactId>vaadin-push</artifactId>
		</dependency>
		<dependency>
			<groupId>com.vaadin</groupId>
			<artifactId>vaadin-client-compiled</artifactId>
		</dependency>
		<dependency>
			<groupId>com.vaadin</groupId>
			<artifactId>vaadin-themes</artifactId>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-war-plugin</artifactId>
				<version>2.6</version>
				<configuration>
					<failOnMissingWebXml>false</failOnMissingWebXml>
					<!-- Exclude an unnecessary file generated by the GWT compiler. -->
					<packagingExcludes>WEB-INF/classes/VAADIN/widgetsets/WEB-INF/**</packagingExcludes>
				</configuration>
			</plugin>
			<plugin>
				<groupId>com.vaadin</groupId>
				<artifactId>vaadin-maven-plugin</artifactId>
				<version>${vaadin.plugin.version}</version>
				<executions>
					<execution>
						<goals>
							<goal>update-theme</goal>
							<goal>update-widgetset</goal>
							<goal>compile</goal>
							<!-- Comment out compile-theme goal to use on-the-fly theme compilation -->
							<goal>compile-theme</goal>
						</goals>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-clean-plugin</artifactId>
				<version>3.0.0</version>
				<!-- Clean up also any pre-compiled themes -->
				<configuration>
					<filesets>
						<fileset>
							<directory>src/main/webapp/VAADIN/themes</directory>
							<includes>
								<include>**/styles.css</include>
								<include>**/styles.scss.cache</include>
							</includes>
						</fileset>
					</filesets>
				</configuration>
			</plugin>

			<!-- The Jetty plugin allows us to easily test the development build by
				running jetty:run on the command line. -->
			<plugin>
				<groupId>org.eclipse.jetty</groupId>
				<artifactId>jetty-maven-plugin</artifactId>
				<version>${jetty.plugin.version}</version>
				<configuration>
					<scanIntervalSeconds>2</scanIntervalSeconds>
				</configuration>
			</plugin>
		</plugins>
	</build>

	<profiles>
		<profile>
			<!-- Vaadin pre-release repositories -->
			<id>vaadin-prerelease</id>
			<activation>
				<activeByDefault>false</activeByDefault>
			</activation>

			<repositories>
				<repository>
					<id>vaadin-prereleases</id>
					<url>http://maven.vaadin.com/vaadin-prereleases</url>
				</repository>
			</repositories>
			<pluginRepositories>
				<pluginRepository>
					<id>vaadin-prereleases</id>
					<url>http://maven.vaadin.com/vaadin-prereleases</url>
				</pluginRepository>
			</pluginRepositories>
		</profile>
	</profiles>

</project>

MyUI.java

package com.howtodoinjava.vaadin.demo;

import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.ui.Button;
import com.vaadin.ui.Label;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

/**
 * This UI is the application entry point. A UI may either represent a browser window 
 * (or tab) or some part of a html page where a Vaadin application is embedded.
 * <p>
 * The UI is initialized using {@link #init(VaadinRequest)}. This method is intended to be 
 * overridden to add component to the user interface and initialize non-component functionality.
 */
@Theme("mytheme")
public class MyUI extends UI {

    @Override
    protected void init(VaadinRequest vaadinRequest) {
        final VerticalLayout layout = new VerticalLayout();
        
        final TextField name = new TextField();
        name.setCaption("Type your name here:");

        Button button = new Button("Click Me");
        button.addClickListener( e -> {
            layout.addComponent(new Label("Thanks " + name.getValue() 
                    + ", it works!"));
        });
        
        layout.addComponents(name, button);
        layout.setMargin(true);
        layout.setSpacing(true);
        
        setContent(layout);
    }

    @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
    @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
    public static class MyUIServlet extends VaadinServlet {
    }
}

If you want to use web.xml file, because your server does not support servlet 3.0 specification, you can use this configuration in web.xml file.

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
	xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
     http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

	<servlet>
		<servlet-name>myservlet</servlet-name>
		<servlet-class>com.vaadin.server.VaadinServlet</servlet-class>
		<init-param>
			<param-name>UI</param-name>
			<param-value>com.howtodoinjava.vaadin.demo.MyUI</param-value>
		</init-param>
	</servlet>

	<servlet-mapping>
		<servlet-name>myservlet</servlet-name>
		<url-pattern>/*</url-pattern>
	</servlet-mapping>
</web-app>

Do not forget to remove @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true) if you are using web.xml file.

Build the generated project

Now it’s time to build the project so that it can download all the dependencies and include into project’s runtime.

$ mvn clean install

Above maven command will download the dependencies (it will take some time), and build the war file VaadinExample-1.0.war.

Run and Test Vaadin Hello World Application

Now it’s time to run the application. In command prompt, run following command to start included jetty server.

$mvn jetty:run

This will start the built-in jetty server and you can access the application at http://localhost:8080/.

Now fill in your name or any string in text box and click on button. It will print the message below the button.

Happy Learning !!

Resources:

Vaadin Archetypes
Vaadin Maven Setup