Java HTTP Server

Introduction to Java HTTP Server

A Java HTTP Server is a server-side application that handles HTTP requests and responses. It is commonly used to build web applications and APIs. Java HTTP servers can be implemented using various frameworks, with Spring Boot and Jakarta EE being two popular choices.

Setting Up a Spring Boot HTTP Server

Spring Boot simplifies the process of setting up a new HTTP server in Java. It allows developers to focus on writing business logic without getting bogged down by configuration. Below, you'll find a step-by-step guide to creating a basic HTTP server using Spring Boot.

First, ensure that you have Java and Maven installed on your system. You can verify the installation by running java -version and mvn -version in your terminal.

The above pom.xml file is a Maven project descriptor that sets up a basic Spring Boot project. It includes the Spring Boot Starter Web dependency, which is essential for building web applications.

Creating a REST Controller

Next, you'll need to create a REST controller that will handle HTTP requests. This is done by defining a class annotated with @RestController and mapping its methods to specific HTTP endpoints using @RequestMapping or related annotations.

In the code above, the HelloController class is a simple REST controller that listens for GET requests at the root endpoint and responds with "Hello, World!". The @GetMapping annotation is used to map the hello method to HTTP GET requests.

Running Your Spring Boot Application

To run your Spring Boot application, navigate to the project root directory and execute the following Maven command:

mvn spring-boot:run

This command starts the embedded Tomcat server and deploys your application. You can access the running app by visiting http://localhost:8080 in your web browser.

Using Jakarta EE for Java HTTP Server

Jakarta EE offers another powerful way to build HTTP servers in Java. It provides specifications for developing enterprise-level applications, including support for servlets, JavaServer Pages (JSP), and Enterprise JavaBeans (EJB).

To set up a Jakarta EE project, you typically use an IDE like Eclipse or IntelliJ IDEA with a compatible application server such as Apache TomEE, WildFly, or Payara.

Below is an example of a simple servlet implementation in Jakarta EE that handles HTTP GET requests:

The HelloServlet class above is a basic servlet that responds to HTTP GET requests at the /hello endpoint. It produces a simple HTML response with "Hello, World!".