Creating and Running a Project with Eclipse · Vaadin
Vaadin Framework - Getting Started - Creating and Running a Project with Eclipse
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Creating and Running a Project with Eclipse

This section gives instructions for creating a new Eclipse project using the Vaadin Plugin. The task will include the following steps:

  1. Create a new project

  2. Write the source code

  3. Configure and start Tomcat (or some other web server)

  4. Open a web browser to use the web application

We also show how you can debug the application in the debug mode in Eclipse.

This walkthrough assumes that you have already installed the Vaadin Plugin for Eclipse and set up your development environment, as instructed in Setting up the Development Environment.

Creating the Project

Let us create the first application project with the tools installed in the previous section. First, launch Eclipse and follow the following steps:

  1. Start creating a new project by selecting from the menu File ▸ New ▸ Project…​.

  2. In the New Project window that opens, select Vaadin ▸ Vaadin 7 Project and click Next.

    myproject new vaadin
  3. In the Vaadin Project step, you need to set the basic web project settings. You need to give at least the project name and the runtime; the default values should be good for the other settings.

    myproject settings
    Project name

    Give the project a name. The name should be a valid identifier usable cross-platform as a filename and inside a URL, so using only lower-case alphanumerics, underscore, and minus sign is recommended.

    Use default location

    Define the directory under which the project is created. The default is under your workspace folder, and you should normally leave it as it is. You may need to set the directory, for example, if you are creating an Eclipse project on top of a version-controlled source tree.

    Target runtime

    Define the application server to use for deploying the application. The server that you have installed, for example Apache Tomcat, should be selected automatically. If not, click New to configure a new server under Eclipse.

    Configuration

    Select the configuration to use; you should normally use the default configuration for the application server. If you need to modify the project facets, click Modify. The recommended Servlet 3.0 configuration uses the @WebServlet deployment, while Servlet 2.4 uses the old web.xml deployment.

    Deployment configuration

    This setting defines the environment to which the application will be deployed, to generate the appropriate project directory layout and configuration files. The choises are:

    • Servlet (default)

    • Google App Engine Servlet

    • Generic Portlet (Portlet 2.0)

    The further steps in the New Project Wizard depend on the selected deployment configuration; the steps listed in this section are for the default servlet configuration. See Google App Engine Integration and Portal Integration for instructions regarding the use of Vaadin in the alternative environments.

    Vaadin version

    Select the Vaadin version to use. The drop-down list shows, by default, the latest available version of Vaadin. The selection includes nightly SNAPSHOT builds, if you want to keep up with the absolutely latest unstable versions.

    You can change the version later in the ivy.xml.

    Create TestBench test

    When enabled, the application stub will include a test case for testing the UI with Vaadin TestBench, as described in Vaadin TestBench. Vaadin TestBench API library will be included in ivy.xml as a dependency. Vaadin version 7.3 or later is required to create the stub.

    You can click Finish here to use the defaults for the rest of the settings, or click Next.

  4. The settings in the Web Module step define the basic web application (WAR) deployment settings and the structure of the web application project. All the settings are pre-filled, and you should normally accept them as they are.

    myproject web
    Context Root

    The context root (of the application) identifies the application in the URL used for accessing it. For example, if the project has a myproject context and a single UI at the context root, the URL would be http://example.com/myproject. The wizard will suggest the project name given in the first step as the context name. You can change the context root later in the Eclipse project properties.

    Content Directory

    The directory containing all the content to be included in the web application (WAR) that is deployed to the web server. The directory is relative to the root directory of the project.

    You can just accept the defaults and click Next.

  5. The Vaadin project step page has various Vaadin-specific application settings. If you are trying out Vaadin for the first time, you should not need to change anything. You can set most of the settings afterwards, except the creation of the portlet configuration.

    myproject vaadin
    Create project template

    Make the wizard create an UI class stub.

    Application Name

    A name for the application UI, shown in the title bar of the browser window.

    Base package name

    The name of the Java package under which the UI class of the application is to be placed.

    Application/UI class name

    The name of the UI class for the application, in which the user interface is developed.

    Portlet version

    When a portlet version is selected (only Portlet 2.0 is supported), the wizard will create the files needed for running the application in a portal. See Portal Integration for more information on portlets.

    Finally, click Finish to create the project.

Exploring the Project

After the New Project wizard exits, it has done all the work for you: an UI class skeleton has been written to src directory and the WebContent/WEB-INF/web.xml contains a deployment descriptor. The project hierarchy shown in the Project Explorer is shown in A New Vaadin Project.

myproject created
Figure 1. A New Vaadin Project

The Vaadin libraries and other dependencies are managed by Ivy. Notice that the libraries are not stored under the project folder, even though they are listed in the Java Resources ▸ Libraries ▸ ivy.xml virtual folder.

The UI Class

The UI class created by the plugin contains the following code:

package com.example.myproject;

import com.vaadin.ui.UI;
...

@SuppressWarnings("serial")
@Theme("myproject")
public class MyprojectUI extends UI {

    @WebServlet(value = "/*", asyncSupported = true)
    @VaadinServletConfiguration(
            productionMode = false,
            ui = MyprojectUI.class)
    public static class Servlet extends VaadinServlet {
    }

    @Override
    protected void init(VaadinRequest request) {
        final VerticalLayout layout = new VerticalLayout();
        layout.setMargin(true);
        setContent(layout);

        Button button = new Button("Click Me");
        button.addClickListener(new Button.ClickListener() {
            public void buttonClick(ClickEvent event) {
                layout.addComponent(
                    new Label("Thank you for clicking"));
            }
        });
        layout.addComponent(button);
    }
}

In a Servlet 3.0 project, the deployment is configured with servlet class and a @WebServlet annotation. The stub includes the servlet class as a static inner class. You may want to refactor it to a separate normal class.

In a Servlet 2.3 project, you would have a web.xml deployment descriptor.

For a more detailed treatment of the deployment, see Using a web.xml Deployment Descriptor.

Coding Tips for Eclipse

One of the most useful features in Eclipse is code completion. Pressing Ctrl+Space in the editor will display a pop-up list of possible class name and method name completions, as shown in Java Code Completion in Eclipse, depending on the context of the cursor position.

codingtips codecompletion
Figure 2. Java Code Completion in Eclipse

To add an import statement for a class, such as Button, simply press Ctrl+Shift+O or click the red error indicator on the left side of the editor window. If the class is available in multiple packages, a list of the alternatives is displayed, as shown in Importing Classes Automatically. For server-side development, you should normally use the classes under the com.vaadin.ui or com.vaadin.server packages. You can not use client-side classes (under com.vaadin.client) or GWT classes for server-side development.

codingtips automaticimports
Figure 3. Importing Classes Automatically

Setting Up and Starting the Web Server

Eclipse IDE for Java EE Developers has the Web Standard Tools package installed, which supports control of various web servers and automatic deployment of web content to the server when changes are made to a project.

Make sure that Tomcat was installed with user permissions. Configuration of the web server in Eclipse will fail if the user does not have write permissions to the configuration and deployment directories under the Tomcat installation directory.

Follow the following steps.

  1. Switch to the Servers tab in the lower panel in Eclipse. List of servers should be empty after Eclipse is installed. Right-click on the empty area in the panel and select New ▸ Server.
    image::img/tomcat-startserver-1.png[]

  2. Select Apache ▸ Tomcat v7.0 Server and set Server’s host name as localhost, which should be the default. If you have only one Tomcat installed, Server runtime has only one choice. Click Next.
    image::img/tomcat-startserver-2.png[]

  3. Add your project to the server by selecting it on the left and clicking Add to add it to the configured projects on the right. Click Finish.
    image::img/tomcat-startserver-3.png[]

  4. The server and the project are now installed in Eclipse and are shown in the Servers tab. To start the server, right-click on the server and select Debug. To start the server in non-debug mode, select Start.
    image::img/tomcat-startserver-4.png[]

  5. The server starts and the WebContent directory of the project is published to the server on http://localhost:8080/myproject/.
    image::img/tomcat-startserver-5.png[]

Running and Debugging

Starting your application is as easy as selecting myproject from the Project Explorer and then Run ▸ Debug As ▸ Debug on Server. Eclipse then opens the application in built-in web browser.

runningMyProject
Figure 4. Running a Vaadin Application

You can insert break points in the Java code by double-clicking on the left margin bar of the source code window. For example, if you insert a breakpoint in the buttonClick() method and click the What is the time? button, Eclipse will ask to switch to the Debug perspective. Debug perspective will show where the execution stopped at the breakpoint. You can examine and change the state of the application. To continue execution, select Resume from Run menu.

debuggingMyProject
Figure 5. Debugging a Vaadin Application

Above, we described how to debug a server-side application. Debugging client-side applications and widgets is described in Debugging Client-Side Code.