import static spark.Spark.*; public class HelloWorld { public static void main(String[] args) { get("/hello", (req, res) -> "Hello World!"); } }

import static spark.Spark.*; public class SimpleExample { public static void main(String[] args) { get("/hello", (req, res) -> "Hello World!"); post("/hello", (req, res) -> "Hello World: " + req.body()); get("/users/:name", (req, res) -> "Selected user: " + req.params(":name") ); get("/news/:section", (req, res) -> { res.type("text/xml"); return "<?xml version=\"1.0\" encoding=\"UTF-8\"?><news>" + req.params("section") + "</news>"; }); } }

import static spark.Spark.*; import java.util.*; public class Books { private static Map<String, Book> books = new HashMap<>(); public static void main(String[] args) { // Create post("/books", (req, res) -> { String author = req.queryParams("author"); String title = req.queryParams("title"); Book book = new Book(author, title); String id = UUID.randomUUID().toString(); books.put(id, book); res.status(201); return id; }); // Read get("/books/:id", (req, res) -> { Book book = books.get(req.params(":id")); if (book != null) { return "Title: " + book.getTitle() + ", Author: " + book.getAuthor(); } else { res.status(404); return "Book not found"; } }); // Update put("/books/:id", (req, res) -> { String id = req.params(":id"); Book book = books.get(id); if (book != null) { String newAuthor = req.queryParams("author"); String newTitle = req.queryParams("title"); if (newAuthor != null) book.setAuthor(newAuthor); if (newTitle != null) book.setTitle(newTitle); return "Book updated"; } else { res.status(404); return "Book not found"; } }); // Delete delete("/books/:id", (req, res) -> { Book book = books.remove(req.params(":id")); if (book != null) { return "Book deleted"; } else { res.status(404); return "Book not found"; } }); } static class Book { private String author, title; public Book(String author, String title) { this.author = author; this.title = title; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } } }

import static spark.Spark.*; import java.util.*; public class FilterExample { private static Map<String, String> users = new HashMap<>(); public static void main(String[] args) { users.put("foo", "bar"); users.put("admin", "admin"); // Authentication filter before((req, res) -> { String user = req.queryParams("user"); String password = req.queryParams("password"); String dbPassword = users.get(user); if (!(password != null && password.equals(dbPassword))) { halt(401, "Unauthorized"); } }); get("/hello", (req, res) -> "Hello World!"); after("/hello", (req, res) -> res.header("X-Custom-Header", "Added by filter") ); } }

import static spark.Spark.*; public class StaticResources { public static void main(String[] args) { // Serve static files from /public in classpath staticFileLocation("/public"); get("/hello", (req, res) -> "Hello World!"); } }

import static spark.Spark.*; public class JsonExample { public static void main(String[] args) { get("/hello", "application/json", (req, res) -> "{\"message\": \"Hello World\"}" ); } }