Simple Java code to demonstrate working with Kafka and Spring Boot (at this time, Spring Boot 3.x)
This project assumes that:
- Apache Maven 3.8.6 or better is installed and in the command path;
- Java 17 or later is installed and available;
- git is installed and available in the command path.
It also pretty well assumes you have a Kafka cluster available for use. The easiest way to achieve that is to use the confluentinc/cp-all-in-one project with Docker (yes, you will need Docker as well) which can run up an ensemble including Kafka and the Confluent schema registry on your desktop. Use of this project is also discussed at Confluent
This is simple to build, however you will need Apache Maven and Java installed.
Basically:
$ git clone git@github.com:TheBellman/SpringKafka.git
$ cd SpringKafka
$ mvn packageall being well, after a few seconds or minutes you should see something like:
[INFO] --- maven-jar-plugin:3.3.0:jar (default-jar) @ springkafka ---
[INFO] Building jar: /Users/robert/Projects/Java/SpringKafka/target/springkafka-0.0.1-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:3.0.0:repackage (repackage) @ springkafka ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.242 s
[INFO] Finished at: 2022-12-10T19:13:00Z
[INFO] ------------------------------------------------------------------------Executing with no other parameters will produce a help message
% java -jar target/springkafka-1.0-SNAPSHOT.jar
11:55:19.201 [main] INFO net.parttimepolymath.spring.springkafka.SpringKafkaToyApplication - Application starting
======================================================================
| Spring Kafka Toy - springkafka:1.0-SNAPSHOT
| built : 2022-12-11T11:54:46Z
======================================================================
2022-12-11T11:55:19.462Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : Starting SpringKafkaToyApplication v1.0-SNAPSHOT using Java 17.0.5 with PID 30369 (/Users/robert/Projects/Java/SpringKafka/target/springkafka-1.0-SNAPSHOT.jar started by robert in /Users/robert/Projects/Java/SpringKafka)
2022-12-11T11:55:19.463Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : The following 1 profile is active: "development"
2022-12-11T11:55:19.685Z INFO 30369 --- [ main] n.p.spring.springkafka.VersionConsumer : Version details : Version(name=Spring Kafka Toy, version=1.0-SNAPSHOT, build=2022-12-11T11:54:46Z, profile=development)
2022-12-11T11:55:19.714Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : Started SpringKafkaToyApplication in 0.449 seconds (process running for 0.648)
usage:
--help print this help message
--consumer run as a data consumer
--producer run as a data producer
--count <count> number of messages to produce
2022-12-11T11:55:19.716Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : Application endingand the same if --help is specified:
% java -jar target/springkafka-1.0-SNAPSHOT.jar --help
11:55:19.201 [main] INFO net.parttimepolymath.spring.springkafka.SpringKafkaToyApplication - Application starting
======================================================================
| Spring Kafka Toy - springkafka:1.0-SNAPSHOT
| built : 2022-12-11T11:54:46Z
======================================================================
2022-12-11T11:55:19.462Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : Starting SpringKafkaToyApplication v1.0-SNAPSHOT using Java 17.0.5 with PID 30369 (/Users/robert/Projects/Java/SpringKafka/target/springkafka-1.0-SNAPSHOT.jar started by robert in /Users/robert/Projects/Java/SpringKafka)
2022-12-11T11:55:19.463Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : The following 1 profile is active: "development"
2022-12-11T11:55:19.685Z INFO 30369 --- [ main] n.p.spring.springkafka.VersionConsumer : Version details : Version(name=Spring Kafka Toy, version=1.0-SNAPSHOT, build=2022-12-11T11:54:46Z, profile=development)
2022-12-11T11:55:19.714Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : Started SpringKafkaToyApplication in 0.449 seconds (process running for 0.648)
usage:
--help print this help message
--consumer run as a data consumer
--producer run as a data producer
--count <count> number of messages to produce
2022-12-11T11:55:19.716Z INFO 30369 --- [ main] n.p.s.s.SpringKafkaToyApplication : Application endingMore typically, you will either want it to execute as the message producer:
% java -jar target/springkafka-1.0-SNAPSHOT.jar --producer --count=1000or message consumer:
% java -jar target/springkafka-1.0-SNAPSHOT.jar --consumerFor the producer, if count is not specified, a default number of messages will be produced. count is ignored for the consumer.
The bootstrap servers defaults to localhost:9092, but you can override this using (e.g.) :
% java -jar target/springkafka-1.0-SNAPSHOT.jar --consumer --spring.kafka.bootstrap-servers=example.net:9092The embedded application.properties hardwires in some assumptions about where thngs can be found. In particular you may want to:
- override the location of the schema registry with
--spring.kafka.properties.schema.registry.url=https://example.com:8081 - override the bootstrap server using
--spring.kafka.bootstrap-servers=example.net:9092
This could be made more "spring" but I'm not going to prioritise this yet.
Copyright 2022 Little Dog Digital
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
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