Java Platform, Enterprise Edition (Java EE) 8 The Java EE Tutorial

## The mood Example Application

The `mood` example application, located in the tut-install`/examples/web/servlet/mood/` directory, is a simple example that displays Duke’s moods at different times during the day. The example shows how to develop a simple application by using the `@WebServlet`, `@WebFilter`, and `@WebListener` annotations to create a servlet, a listener, and a filter.

The following topics are addressed here:

- Components of the mood Example Application

- Running the mood Example

### Components of the mood Example Application

The `mood` example application is comprised of three components: `mood.web.MoodServlet`, `mood.web.TimeOfDayFilter`, and `mood.web.SimpleServletListener`.

`MoodServlet`, the presentation layer of the application, displays Duke’s mood in a graphic, based on the time of day. The `@WebServlet` annotation specifies the URL pattern:

    @WebServlet("/report")
    public class MoodServlet extends HttpServlet {
        ...

`TimeOfDayFilter` sets an initialization parameter indicating that Duke is awake:

    @WebFilter(filterName = "TimeOfDayFilter",
    urlPatterns = {"/*"},
    initParams = {
        @WebInitParam(name = "mood", value = "awake")})
    public class TimeOfDayFilter implements Filter {
        ...

The filter calls the `doFilter` method, which contains a `switch` statement that sets Duke’s mood based on the current time.

`SimpleServletListener` logs changes in the servlet’s lifecycle. The log entries appear in the server log.

### Running the mood Example

You can use either NetBeans IDE or Maven to build, package, deploy, and run the `mood` example.

The following topics are addressed here:

- To Run the mood Example Using NetBeans IDE

- To Run the mood Example Using Maven

#### To Run the mood Example Using NetBeans IDE

1. Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).

2. From the File menu, choose Open Project.

3. In the Open Project dialog box, navigate to:

       tut-install/examples/web/servlet

4. Select the `mood` folder.

5. Click Open Project.

6. In the Projects tab, right-click the `mood` project and select Build.

7. In a web browser, enter the following URL:

       http://localhost:8080/mood/report

   The URL specifies the context root, followed by the URL pattern.

   A web page appears with the title "Servlet MoodServlet at /mood", a text string describing Duke’s mood, and an illustrative graphic.

#### To Run the mood Example Using Maven

1. Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).

2. In a terminal window, go to:

       tut-install/examples/web/servlet/mood/

3. Enter the following command to deploy the application:

       mvn install

4. In a web browser, enter the following URL:

       http://localhost:8080/mood/report

   The URL specifies the context root, followed by the URL pattern.

   A web page appears with the title "Servlet MoodServlet at /mood", a text string describing Duke’s mood, and an illustrative graphic.

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