Using Spring Boot's Embedded Web Server

Welcome to our article on Using Spring Boot's Embedded Web Server! Here, you can get training on how to leverage Spring Boot's built-in features effectively. Spring Boot has revolutionized the way Java developers build and deploy applications by integrating a range of functionalities, including its embedded web server capabilities. This article will provide you with a comprehensive understanding of embedded web servers in Spring Boot, covering configuration, deployment, and practical insights to enhance your development experience.

Overview of Embedded Web Servers

Spring Boot simplifies web application development by providing an embedded web server. This means that developers can run their applications without needing to deploy them on an external server. The embedded server becomes part of the application itself, which streamlines the development process and leads to faster deployment cycles.

What are Embedded Web Servers?

Embedded web servers are server software integrated into an application, allowing it to handle HTTP requests directly. This eliminates the need for a separate application server, making it easier to package and distribute applications. Spring Boot supports several embedded web servers, including Apache Tomcat, Jetty, and Undertow, each with its own strengths and use cases.

The beauty of using embedded servers is that they facilitate rapid development with minimal configuration. By default, Spring Boot applications use Tomcat, but switching to Jetty or Undertow is straightforward, making it adaptable to various project requirements.

Benefits of Using Embedded Web Servers

• Simplified Deployment: With an embedded server, you can create a self-contained JAR file that includes your application and server, making it easy to share and deploy.
• Reduced Configuration: Spring Boot's auto-configuration capabilities help reduce boilerplate code and configuration for setting up the web server.
• Development Flexibility: Developers can easily switch between different embedded servers based on their project needs without significant changes to the application code.
• Improved Testing: Embedded servers facilitate easy testing and debugging, as developers can run their applications locally without additional server setup.

Configuring Tomcat and Jetty

Configuring Tomcat

Tomcat is the default embedded web server in Spring Boot. It comes pre-configured with sensible defaults, but you may want to customize certain aspects to suit your application’s needs.

To include Tomcat in your Spring Boot application, you can use Maven or Gradle. For Maven, add the following dependency in your pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

This starter includes Tomcat by default. If you want to customize the Tomcat settings, you can do so in the application.properties file. For example:

server.port=8081
server.servlet.context-path=/myapp

This configuration changes the default port to 8081 and sets the context path to /myapp.

Configuring Jetty

If you prefer Jetty over Tomcat, switching is simple. First, exclude Tomcat from your Maven dependencies and add the Jetty starter. In your pom.xml, it would look like this:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jetty</artifactId>
</dependency>

With Jetty as your embedded server, you can configure it similarly through application.properties. For instance, to set the port and a different context path, you can use:

server.port=8082
server.servlet.context-path=/myjettyapp

Understanding Server Properties

The server properties in application.properties or application.yml help you manage various aspects of your embedded server. Here are some critical properties you might consider:

• server.port: The port on which the server will listen for requests.
• server.servlet.context-path: The context path for your application.
• server.error.whitelabel.enabled: Disable the default error page if you want to handle errors differently.

Utilizing these configurations allows you to tailor the server behavior according to your application requirements.

Deploying Applications with Embedded Servers

Deploying a Spring Boot application with an embedded server is a straightforward process. Since the application is packaged as a self-contained JAR file, the deployment can be as simple as running the JAR on any machine with Java installed.

Packaging the Application

To create a deployable JAR file, you can use Maven or Gradle. For Maven, execute the following command:

mvn clean package

This command generates a JAR file in the target directory. The JAR file will include all dependencies, including the embedded server.

Running the Application

To run your Spring Boot application, navigate to the directory containing the generated JAR file and execute:

java -jar yourapp.jar

Replace yourapp.jar with the name of your generated file. This command starts the embedded web server, and your application will be accessible at http://localhost:8081/myapp (or the port and context path you configured).

Deploying to Production

When deploying to production, consider using a cloud provider or container orchestration platform like Kubernetes. The self-contained JAR file simplifies deployment in such environments. You can create Docker images for your Spring Boot application to facilitate containerization.

Here is a basic Dockerfile example:

FROM openjdk:11-jre-slim
VOLUME /tmp
COPY target/yourapp.jar app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

By building your Docker image and pushing it to a container registry, you can deploy your application on any container orchestration platform seamlessly.

Summary

In this article, we explored Using Spring Boot's Embedded Web Server, emphasizing the benefits and configurations of embedded servers like Tomcat and Jetty. We discussed how to set up, configure, and deploy applications using these embedded servers, highlighting the ease of use and flexibility they provide to developers.

Spring Boot's embedded web server feature not only simplifies the development and deployment processes but also enhances your application's portability and scalability. Whether you're developing microservices or full-fledged applications, leveraging embedded servers can significantly boost your productivity.

For further exploration, consider referring to the official Spring Boot documentation for more in-depth insights and advanced configuration options.

Last Update: 28 Dec, 2024