Spring Boot and Kafka example

In this tutorial, we're gonna build a Spring Boot application with Kafka applying the concepts of Event-Driven Architecture, Producers, and Consumers. In this application, we are simulating one spring boot application (PRODUCER) that a customer can place an order and another application that simulate a transportation officer (CONSUMER). When the customer places an order the Transportation Officer consumes this information, using Apache Kafka and Event-Driven Architecture, to know if the order is ready for shipping, and can automatically collect the package.

Technologies

Spring Boot

Apache Kafka

Apache Zookeeper

Docker

Java 8

REST

Main Classes

• OrderController - Responsible to receive the POST request /orders (place a order) - See REST CONTROLLER
• OrderProducer - Responsible to publish (write) a event in kafka topic (order-topic) - See Kafka Documentation
• TransportationOfficerConsumer - Responsible to subscribe the event(order-topic), read and process the event place order

Run Docker and Spring Boot applications

• Initialize Zookeeper and Kafka, in folder kafka-springboot-integration run:

docker-compose up

• Build the applications:

mvn clean package

• Initialize the projects CONSUMER AND PRODUCER:

cd producer
mvn spring-boot:run

cd consumer
mvn spring-boot:run

The consumer project doesn't have an endpoint, it onlys conect to the order topic to listening the stream

Download POSTMAN for JSON requests.

PLACE AN ORDER

• Open your postman application in localhost:8080/orders
• METHOD: POST
• BODY: raw - type JSON

{
 "identifier":1,
 "customer": "CUSTOMER 1",
 "value": 1200,
 "address":"SQNW 309 bl. D apt 305",
 "zipcode": "70686456"
}

• RETURN - 200 OK

EXPECTED RESULTS - IN CONSOLE

• PRODUCER

============= PRODUCER ======================
Receive the Order: 
{
 "identifier":1,
 "customer": "CUSTOMER 1",
 "value": 1200,
 "adress":"SQNW 309 bl. D apt 305",
 "zipcode": "70686456"
}
Process the payment: OK 

Packing: OK 

=============================================

• CONSUMER

============= CONSUMER ======================
key: 0d2d5a8a-ead4-4c62-8dbd-da7d44319c89
Headers: RecordHeaders(headers = [], isReadOnly = false)
Partion: 0
Receive the Order: 
{
 "identifier":1,
 "customer": "CUSTOMER 1",
 "value": 1200,
 "adress":"SQNW 309 bl. D apt 305",
 "zipcode": "70686456"
}
Collect the package: OK 

Shipping the package: OK 

=============================================