Professional Java for Web Applications

Chapter 3Writing Your First Servlet

IN THIS CHAPTER

• Creating a Servlet class
• Configuring a Servlet for deployment
• Understanding doGet(), doPost() and other methods
• Using parameters and accepting form submissions
• Configuring your application using init parameters
• Uploading files from a form
• Making your application safe for multithreading

WROX.COM CODE DOWNLOADS FOR THIS CHAPTER

You can find the wrox.com code downloads for this chapter at www.wrox.com/go/projavaforwebapps on the Download Code tab. The code for this chapter is divided into the following major examples:

• Hello-World Project
• Hello-User Project
• Customer-Support-v1 Project

NEW MAVEN DEPENDENCIES FOR THIS CHAPTER

In this chapter, you’ll need your first Maven dependency, shown in the following code. You’ll use this dependency for every chapter throughout the rest of the book.

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

In the last chapter, you became familiar with application servers and web containers and learned how to run, deploy to, and debug Apache Tomcat 8.0 from your Java IDE. In this chapter, you begin building web applications by first exploring the world of Servlets. Throughout this chapter and the rest of the book, you’ll continually change and improve these applications, deploying them to Tomcat for testing and debugging.

CREATING A SERVLET CLASS

In the Java Platform, Enterprise Edition, a