Spark - ein winziges Web-Framework für Java 8

Spark 2.9.4 ist da!!

<dependency>
    <groupId>com.sparkjava</groupId>
    <artifactId>spark-core</artifactId>
    <version>2.9.4</version>
</dependency>

Sponsern Sie das Projekt hier https://github.com/sponsors/perwendel

Für die Dokumentation besuchen Sie bitte: http://sparkjava.com/documentation

Bei Fragen zur Nutzung verwenden Sie bitte Stack Overflow mit dem Tag „spark-java“

Javadoc: http://javadoc.io/doc/com.sparkjava/spark-core

Beim Committen in das Projekt verwenden Sie bitte das Spark-Format, das in https://github.com/perwendel/spark/blob/master/config/spark_formatter_intellij.xml konfiguriert ist

Erste Schritte

<dependency>
    <groupId>com.sparkjava</groupId>
    <artifactId>spark-core</artifactId>
    <version>2.9.4</version>
</dependency>

import static spark.Spark.*;

public class HelloWorld {
    public static void main(String[] arg){
        get("/hello", (request, response) -> "Hello World!");
    }
}

Ansehen unter: http://localhost:4567/hello

Schauen Sie sich die Beispiele im Quellcode an und probieren Sie sie aus. Sie können sich auch das Javadoc ansehen. Nachdem Sie den Quellcode von github bezogen haben, führen Sie aus:

mvn javadoc:javadoc

Das Ergebnis wird in /target/site/apidocs abgelegt

Beispiele

Einfaches Beispiel, das einige grundlegende Funktionen zeigt

import static spark.Spark.*;

/**
 * A simple example just showing some basic functionality
 */
public class SimpleExample {

    public static void main(String[] args) {

        //  port(5678); <- Uncomment this if you want spark to listen to port 5678 instead of the default 4567

        get("/hello", (request, response) -> "Hello World!");

        post("/hello", (request, response) ->
            "Hello World: " + request.body()
        );

        get("/private", (request, response) -> {
            response.status(401);
            return "Go Away!!!";
        });

        get("/users/:name", (request, response) -> "Selected user: " + request.params(":name"));

        get("/news/:section", (request, response) -> {
            response.type("text/xml");
            return "<?xml version=\"1.0\" encoding=\"UTF-8\"?><news>" + request.params("section") + "</news>";
        });

        get("/protected", (request, response) -> {
            halt(403, "I don't think so!!!");
            return null;
        });

        get("/redirect", (request, response) -> {
            response.redirect("/news/world");
            return null;
        });

        get("/", (request, response) -> "root");
    }
}

---

Ein einfaches CRUD-Beispiel, das zeigt, wie man Buchressourcen erstellt, abruft, aktualisiert und löscht

import static spark.Spark.*;

import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * A simple CRUD example showing how to create, get, update and delete book resources.
 */
public class Books {

    /**
     * Map holding the books
     */
    private static Map<String, Book> books = new HashMap<String, Book>();

    public static void main(String[] args) {
        final Random random = new Random();

        // Creates a new book resource, will return the ID to the created resource
        // author and title are sent in the post body as x-www-urlencoded values e.g. author=Foo&title=Bar
        // you get them by using request.queryParams("valuename")
        post("/books", (request, response) -> {
            String author = request.queryParams("author");
            String title = request.queryParams("title");
            Book book = new Book(author, title);

            int id = random.nextInt(Integer.MAX_VALUE);
            books.put(String.valueOf(id), book);

            response.status(201); // 201 Created
            return id;
        });

        // Gets the book resource for the provided id
        get("/books/:id", (request, response) -> {
            Book book = books.get(request.params(":id"));
            if (book != null) {
                return "Title: " + book.getTitle() + ", Author: " + book.getAuthor();
            } else {
                response.status(404); // 404 Not found
                return "Book not found";
            }
        });

        // Updates the book resource for the provided id with new information
        // author and title are sent in the request body as x-www-urlencoded values e.g. author=Foo&title=Bar
        // you get them by using request.queryParams("valuename")
        put("/books/:id", (request, response) -> {
            String id = request.params(":id");
            Book book = books.get(id);
            if (book != null) {
                String newAuthor = request.queryParams("author");
                String newTitle = request.queryParams("title");
                if (newAuthor != null) {
                    book.setAuthor(newAuthor);
                }
                if (newTitle != null) {
                    book.setTitle(newTitle);
                }
                return "Book with id '" + id + "' updated";
            } else {
                response.status(404); // 404 Not found
                return "Book not found";
            }
        });

        // Deletes the book resource for the provided id
        delete("/books/:id", (request, response) -> {
            String id = request.params(":id");
            Book book = books.remove(id);
            if (book != null) {
                return "Book with id '" + id + "' deleted";
            } else {
                response.status(404); // 404 Not found
                return "Book not found";
            }
        });

        // Gets all available book resources (ids)
        get("/books", (request, response) -> {
            String ids = "";
            for (String id : books.keySet()) {
                ids += id + " ";
            }
            return ids;
        });
    }

    public static class Book {

        public 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;
        }
    }
}

---

Beispiel, das einen sehr einfachen (und dummen) Authentifizierungsfilter zeigt, der vor allen anderen Ressourcen ausgeführt wird

import static spark.Spark.*;

import java.util.HashMap;
import java.util.Map;

/**
 * Example showing a very simple (and stupid) authentication filter that is
 * executed before all other resources.
 *
 * When requesting the resource with e.g.
 *     http://localhost:4567/hello?user=some&password=guy
 * the filter will stop the execution and the client will get a 401 UNAUTHORIZED with the content 'You are not welcome here'
 *
 * When requesting the resource with e.g.
 *     http://localhost:4567/hello?user=foo&password=bar
 * the filter will accept the request and the request will continue to the /hello route.
 *
 * Note: There is a second "before filter" that adds a header to the response
 * Note: There is also an "after filter" that adds a header to the response
 */
public class FilterExample {