Beer is a lightweight Java library that makes it simple to build RESTful web applications using Jetty and Servlets — without the boilerplate. Just pour your routes, filters, static files, and you’re ready to serve!

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✨ Features

• ✅ Simple route handling — define GET, POST, PUT, DELETE handlers with ease.
• ✅ WebSocket handling — define WebSocket handlers just as easily.
• ✅ Wildcard routes — match dynamic paths effortlessly.
• ✅ Path parameters support — e.g. /myPath/:pathParam.
• ✅ Filters & CORS — add pre-processing, logging, or CORS in one line.
• ✅ Serve static files — host static content alongside your API.
• ✅ HTTPS support — configure SSL out of the box.
• ✅ Centralized exception handling — return clear JSON error responses.
• ✅ Runs on Jetty — robust, proven, and production-ready.

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🚀 Quick Start

import gr.kgdev.beer.core.Beer;
import gr.kgdev.beer.utils.BeerUtils;
import gr.kgdev.beer.model.SimpleMessage;

public class App {
    public static void main(String[] args) throws Exception {
        var beer = new Beer();

        var config = 
            new BeerConfig()
                .setIp("0.0.0.0")
                .setPort(8080)
                .setLoggerName("beer")
                .setJettyMinThreads(4)
                .setJettyMaxThreads(32)
                .setJettyIdleTimeout(60000);
                // .setKeystorePath("path/to/keystore"); // For HTTPS
                // .setKeystorePass("yourPassword");

        beer.init(config);

        // serve static files from classpath /public (in jar folder)
        beer.staticFiles("/", "/public");

        // common filters provided by beer
        beer.corsAllFilter();
        beer.loggingFilter();
        beer.exceptionFilter();
        // user defined filter
        beer.filter("/*", (req, res) -> System.out.println("Request filtered!"));

        // beer automatically converts returned object to json
        beer.get("/hello", (req, res) -> Map.of("message", "Hello Beer!"));
        beer.get("/hello-class", (req, res) -> new SimpleMessage("Hello Beer!"));
        beer.post("/echo", (req, res) -> {
            var body = BeerUtils.parseReqBody(req);
            return Map.of("you_sent", body);
        });
        // do not forget to call start!
        beer.start();
    }
}

Beer is designed for primarily creating restful services with json responses. But it is possible to override the default behavior and return any other kind of response. Html response example:

    beer.get("/reset-password", (req, res) -> {
        // add content type header in order to return html response
        res.setHeader("Content-Type", "text/html; charset=utf-8");
        return FileUtils.readResourceFile("reset-password.html");
    });

🏗️ Core Concept

The core class is Beer.

This is where the main capabilities live:

• init() — Configures your server with a BeerConfig.
• filter() — Attaches custom servlet filters.
• get(), post(), put(), delete() — Registers route handlers.
• socket() — Registers WebSocket handlers.
• broadcast() — Sends data to WebSocket connections.
• exceptionFilter() — Handles uncaught exceptions globally.
• corsAllFilter() — Enables permissive CORS for all routes.
• loggingFilter() — Logs all incoming requests.
• staticFiles() — Serves static files from your classpath.
• start() — Starts the Jetty server.

🛠️ Utilities

Beer is a thin layer built on top of Servlets, so it includes helper classes to simplify request/response handling.
The most important one is BeerUtils.

BeerUtils Overview

• parseReqBody() — Reads the request body as a raw string.
• parseBody() — Converts the JSON request body into a Java object of the given class.
• parseQueryParams() — Maps query parameters into a Java object.
• getPathParam() — Extracts a named path parameter (e.g. :id in /users/:id).
• parseBasicAuthCredentials() — Parses HTTP Basic Authentication headers and returns a Credentials object.
• getPathSegment() — Gets a specific segment from the request URI by index.
• redirect() — Sends an HTTP redirect to the given URL.
• json() — Converts a Java object, collection, map, or string into a proper JSON string.

💡 Inspiration

Beer is inspired by the simplicity of Spark and Express — but built directly on top of Jetty and Servlets to give you control, clarity, and lightweight performance with minimal setup.