DOCSP-61803: JavaRS Getting Started

README.md

@@ -13,7 +13,7 @@ includes its own setup instructions.
 - Hibernate
 - Kotlin Coroutine
 - Kotlin Sync
-- Java Reactive Streams
+- [Java Reactive Streams](java-rs/hello-world/README.md) 
 - Java Sync
 - [.NET/C#](dotnet/hello-world/README.md)
 - [Node.js](node/hello-world/README.md)

java-rs/hello-world/.gitignore

@@ -0,0 +1 @@
+target/

java-rs/hello-world/README.md

@@ -0,0 +1,69 @@
+# Get Started with the MongoDB Java Reactive Streams Driver
+
+This sample application connects to a MongoDB deployment, seeds a small
+set of sample product documents, and retrieves one of them. Because the
+app inserts its own data, you don't need to load an external dataset.
+
+The app uses the MongoDB Reactive Streams Java driver together with
+[Project Reactor](https://projectreactor.io/) to consume the `Publisher`
+results that the driver returns.
+
+## Prerequisites
+
+Before you begin, complete the [Atlas Get Started guide](https://www.mongodb.com/docs/get-started/)
+to create a free Atlas deployment and save your database user
+credentials.
+
+You also need the following components installed in your development environment:
+
+- JDK version 21 or later
+- Maven
+
+## Installation
+
+Clone this repository:
+
+```bash
+git clone https://github.com/mongodb/mongodb-code-examples
+```
+
+Install the MongoDB Java Reactive Streams driver.  Follow the
+[Java Reactive Streams installation guide](https://www.mongodb.com/docs/languages/java/reactive-streams-driver/current/getting-started/)
+for your platform.
+
+
+Navigate into the `java-rs/hello-world` project directory and compile the
+application:
+
+```bash
+cd mongodb-code-examples/java-rs/hello-world
+mvn compile
+```
+
+## Connect to MongoDB
+
+Set your connection string as an environment variable, replacing
+`<connection string uri>` with your connection string:
+
+```bash
+export MONGODB_URI="<connection string uri>"
+```
+
+## Run the Application
+
+```bash
+mvn compile exec:java
+```
+
+When you run the app, it inserts a few product documents into the
+`get_started.products` collection, then queries and prints one of them:
+
+```
+{"_id": {"$oid": "..."}, "name": "Wireless Mouse", "category": "Electronics", "price": 24.99, "tags": ["wireless", "usb", "ergonomic"]}
+```
+
+You can run the app more than once. It clears the collection before
+each run, so the results stay consistent.
+
+If you encounter an error or see no output, verify that you set the
+`MONGODB_URI` environment variable correctly.

java-rs/hello-world/pom.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.mongodb</groupId>
+    <artifactId>hello-world-reactive-streams</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+
+    <properties>
+        <maven.compiler.release>21</maven.compiler.release>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <exec.mainClass>HelloWorld</exec.mainClass>
+    </properties>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.mongodb</groupId>
+                <artifactId>mongodb-driver-bom</artifactId>
+                <version>5.9.1</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+            <dependency>
+                <groupId>io.projectreactor</groupId>
+                <artifactId>reactor-bom</artifactId>
+                <version>2025.0.0</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.mongodb</groupId>
+            <artifactId>mongodb-driver-reactivestreams</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.projectreactor</groupId>
+            <artifactId>reactor-core</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.5.0</version>
+            </plugin>
+        </plugins>
+    </build>
+</project>

java-rs/hello-world/src/main/java/HelloWorld.java

@@ -0,0 +1,50 @@
+import static com.mongodb.client.model.Filters.eq;
+
+import com.mongodb.reactivestreams.client.MongoClient;
+import com.mongodb.reactivestreams.client.MongoClients;
+import com.mongodb.reactivestreams.client.MongoCollection;
+import com.mongodb.reactivestreams.client.MongoDatabase;
+import java.util.List;
+import org.bson.Document;
+import reactor.core.publisher.Mono;
+
+public class HelloWorld {
+
+    // A few sample product documents seeded by this app so you can run
+    // it without loading an external dataset.
+    private static final List<Document> SAMPLE_PRODUCTS = List.of(
+        new Document("name", "Wireless Mouse")
+            .append("category", "Electronics")
+            .append("price", 24.99)
+            .append("tags", List.of("wireless", "usb", "ergonomic")),
+        new Document("name", "Standing Desk")
+            .append("category", "Furniture")
+            .append("price", 349.99)
+            .append("tags", List.of("adjustable", "office")),
+        new Document("name", "Noise-Cancelling Headphones")
+            .append("category", "Electronics")
+            .append("price", 199.99)
+            .append("tags", List.of("bluetooth", "wireless", "over-ear"))
+    );
+
+    public static void main(String[] args) {
+        String uri = System.getenv("MONGODB_URI");
+
+        try (MongoClient client = MongoClients.create(uri)) {
+            MongoDatabase database = client.getDatabase("get_started");
+            MongoCollection<Document> products = database.getCollection("products");
+
+            // Each reactive driver call returns a Publisher. Wrapping it in a
+            // Reactor Mono and calling block() runs the operation and waits for
+            // it to complete before moving on.
+
+            // Seed the collection so the app has data to query. Clearing the
+            // collection first keeps results consistent across repeated runs.
+            Mono.from(products.deleteMany(new Document())).block();
+            Mono.from(products.insertMany(SAMPLE_PRODUCTS)).block();
+
+            Document product = Mono.from(products.find(eq("name", "Wireless Mouse")).first()).block();
+            System.out.println(product.toJson());
+        }
+    }
+}