How to deploy web application on the tomcat server

Key takeaways:

• Tomcat is an open-source server designed to run Java-based web applications, including servlets and JSP.

• Applications are deployed using WAR files, which can be created using Maven.

• Key directories in Tomcat include bin for scripts, conf for configuration, and webapps for deployed applications.

• To start Tomcat, run commands in the bin directory based on your operating system (Windows, macOS, Linux).

• The pom.xml file is essential in Maven for defining project details, dependencies, and build configurations.

• Create a WAR file by running Maven in the project directory with the pom.xml file.

• Deploy the WAR file by placing it in the webapps directory on the running Tomcat server.

• Access the deployed application via http://localhost:8080 with the appropriate WAR file name.

Tomcat is an open-source server specifically designed to run Java-based web applications. These Java-based applications specifically have Java servlets and JavaServer Pages(JSP). We are going to use Maven to create a customized web application archive file (WAR) to deploy the web application on the containers. The WAR files pack the web application to make deploying it easier on the deployment containers.

Deploying a web application

There are two ways to deploy the application on Tomcat: manually and through its manager. In this Answer, we are focused on deploying the application manually. There are a series of steps that we need to follow to successfully deploy the Java Server Pages web application on the Tomcat server. The process goes from understanding the directory structure to deploying the web app on Tomcat.

Start the Tomcat server

First, we need to install Tomcat on our desktop. Once we have installed Tomcat, the next step is to understand its structure.

1. bin: Contains the scripts for starting and shutting down the server. We use catalina.sh or catalina.bat for starting, restarting, and stopping the server.

2. conf: Contains configuration files for Tomcat. The server.xml file has the main configuration and tomcat-users.xml has the roles for Tomcat Manager applications.

3. webapps: Contains the web applications and WAR files to be deployed on the Tomcat server.

Now that we understand the structure, let’s explore the steps to deploy the web application on the server.

For this purpose, navigate to the /bin directory and start the Tomcat server using the command.

On Windows, run the following command:

On macOS and Linux, run the following command:

Preparing the application for deployment

We need a Java web application and a pom.xml file to create a WAR file. We use Maven, a project management and build application tool, to create the WAR file of the Java web application. The Maven project, however, requires a Project Object Model pom.xml file.

Defining the pom.xml file

The pom.xml file contains build configuration, build plugins, project information details, and profiles for the web application.

To create a pom.xml file, we define the following key elements:

1. Project information:

• <groupId>: Defines organization responsible for project.

• <artifactId>: Unique identifier for the project.

• <version>: Defines the version of project.

2. Dependencies:

• <dependencies>: Defines external dependencies to the project.

• <dependency>: Each dependency has its artifact ID and version.

3. Build configuration:

• <plugins>: Specifies all the build plugins for project.

• <plugin>: Each plugin has its artifact ID and version.

4. Repositories:

• <respositories>: Specify external repositories to search for repositories.

5. Reporting:

• <reporting>: Specify reporting plugin with their configuration.

6. Properties:

• <properties>: It helps define properties to use throughout the projecy model file.

To build the application into a WAR file. Run the following command in the directory containing the web application and the pom.xml file.

As a result, you will find the target directory added to your project directory /sample-app. You will find your WAR file in the directory /sample-app/target. Now, the web application is ready for deployment.

Deploy and access the application

We need to place the prepared web application WAR file in the /webapps directory on Tomcat. Wait for the application to be deployed on the running Tomcat server. Our WAR file name is ROOT.war, so we wait until we get the following command in the terminal.

Now, if you go to http://localhost:8080, you will find your deployed web application. The port 8080 is the specified port for Tomcat. We have used ROOT.war file to deploy our web application, so the URL has no directory. If, for example, the WAR file is web-app.war, you will find your deployed web application at http://localhost:8080/web-app.

Now that we have gone through the deployment process, see how the web application is deployed on the server. You can add value to the parameter using the GET request; this can be done by adding the following URL.

On our platform, you can use the following URL.

To use the above URL, please first "Run" the following widget, and once the app is deployed, please visit the app URL.

This is how we can successfully deploy the Java Server Pages web application on the Tomcat server.

The process works in flow from building the application to building the environment for deploying the built version of the application. Tomcat must define the web application and the Maven plug-ins to successfully execute the web application on the server.

Conclusion

In conclusion, deploying Java-based web applications on a Tomcat server is a structured process involving the creation of a WAR file, configuring key project details through Maven, and understanding the Tomcat directory structure. By following the steps of starting the server, preparing the application, and placing the WAR file in the appropriate directory, developers can efficiently deploy and access their applications. Tomcat provides a reliable platform for running Java servlets and JSP, making it a preferred choice for hosting Java web applications.