quickstarts/pub_sub/java/http/README.md

Dapr pub/sub

In this quickstart, there is a publisher microservice checkout and a subscriber microservice order-processor to demonstrate how Dapr enables a publish-subscribe pattern. checkout generates messages and publishes to a specific orders topic, and order-processor subscribers listen for messages of topic orders.

Visit this link for more information about Dapr and Pub-Sub.

Note: This example leverages HTTPClient only. If you are looking for the example using the Dapr Client SDK (recommended) click here.

This quickstart includes one publisher:

• Java client message generator checkout

And one subscriber:

• Java subscriber order-processor

Pre-requisites

• Dapr and Dapr Cli.
• Java JDK 11 (or greater): Oracle JDK or OpenJDK.
• Apache Maven version 3.x.

Run Java message publisher app with Dapr

1. Open a new terminal window and navigate to checkout directory:

cd checkout

2. Install dependencies:

mvn clean install

3. Run the Java publisher app with Dapr:

 dapr run --app-id checkout --components-path ../../../components -- java -jar target/CheckoutService-0.0.1-SNAPSHOT.jar

Run Java message subscriber app with Dapr

1. Open a new terminal window and navigate to order-processor directory:

cd order-processor

2. Install dependencies:

mvn clean install

3. Run the Java subscriber app with Dapr:

 dapr run --app-port 8080 --app-id order-processor --components-path ../../../components -- java -jar target/OrderProcessingService-0.0.1-SNAPSHOT.jar