Using Spring Boot with JCache and Hazelcast

See something wrong? Edit this page.

This guide will get you started to use Hazelcast via JCache provider for your Spring Boot application.

You can see the whole project here.

What You’ll Learn

In this guide, you’ll deploy a Spring Boot application that uses JCache with Hazelcast implementation.

Prerequisites

  • ~5 minutes

  • JDK 1.8+

  • Apache Maven 3.2+

Spring Boot Application

To leverage JCache in your Spring Boot application, you will need to:

  • add org.springframework.boot:spring-boot-starter-cache dependency

  • add @EnableCaching annotation to your main class

  • add @CacheResult(cacheName = "books") annotation to every method you want to cache

  • add spring.cache.type=jcache to your application.properties file

For more explanation on the Spring Boot and JCache topic, please check the related Spring Boot blog post: Cache Abstraction: JCache.

In our case, let’s have a simple web service with two classes defined as follows:

BookController.java
@RestController
@RequestMapping("/books")
public class BookController {

    private final BookService bookService;

    BookController(BookService bookService) {
        this.bookService = bookService;
    }

    @GetMapping("/{isbn}")
    public String getBookNameByIsbn(@PathVariable("isbn") String isbn) {
        return bookService.getBookNameByIsbn(isbn);
    }
}
BookService.java
@Service
public class BookService {
    @CacheResult(cacheName = "books")
    public String getBookNameByIsbn(String isbn) {
        return findBookInSlowSource(isbn);
    }

    private String findBookInSlowSource(String isbn) {
        // some long processing
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            throw new RuntimeException(e);
        }
        return "Sample Book Name";
    }
}

The idea is that every call to the endpoint /books/<isbn> would go to the method findBookNameByIsbn(), which would attempt to return cached results.

If there’s no cached value, the method would be executed and results cached.

Using Hazelcast as JCache Provider

We want to use Hazelcast as the JCache provider. The good news is that all you have to do is to add Hazelcast to your classpath:

pom.xml
<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>hazelcast-all</artifactId>
</dependency>

Then, you need to create a Hazelcast configuration with the books map configured. You can define it as src/main/resources/hazelcast.yaml.

hazelcast.yaml
hazelcast:
  cache:
    books:
      management-enabled: true

Finally, you can configure your application to use Hazelcast. You can use either client-server or embedded topology.

Client-server Configuration

You first need to start a Hazelcast server with the Hazelcast configuration defined in the previous step.

  • Docker

  • CLI

docker run --rm -p 5701:5701 -v $(pwd)/src/main/resources:/hazelcast -e JAVA_OPTS="-Dhazelcast.config=/hazelcast/hazelcast.yaml" hazelcast/hazelcast
# Install Hazelcast CLI as described at
# https://github.com/hazelcast/hazelcast-command-line#installation

wget https://repo1.maven.org/maven2/javax/cache/cache-api/1.1.1/cache-api-1.1.1.jar
hz start -c src/main/resources/hazelcast.yaml -j cache-api-1.1.1.jar

Then, use the following application.properties for your Spring Boot application.

application.properties
spring.cache.type=jcache
spring.cache.jcache.provider=com.hazelcast.client.cache.HazelcastClientCachingProvider
spring.hazelcast.config=classpath:hazelcast-client.yaml

To start the application, run the following command.

mvn spring-boot:run

Embedded Hazelcast Configuration

If you prefer to run Hazelcast embedded in your Spring Boot application, then you need to use the following application-embedded.properties file.

application-embedded.properties
spring.cache.type=jcache
spring.cache.jcache.provider=com.hazelcast.cache.impl.HazelcastServerCachingProvider
spring.hazelcast.config=classpath:hazelcast.yaml

To start the application, run the following command.

mvn spring-boot:run -Dspring-boot.run.profiles=embedded

Testing the Application

You should see that your application is successfully connected to Hazelcast.

Members {size:1, ver:1} [
        Member [172.30.63.9]:5701 - 75cd0b19-ee36-4e0a-9d9c-38c49f67f842 this
]

Then, you can test the application by executing the following command.

curl localhost:8080/books/12345
Sample Book Name

The first time you execute this command, it should take some time to get the response. However, when you try it again, it should be instant. That means that the cache is used.

curl localhost:8080/books/12345
Sample Book Name

What’s more?

If your want to learn more about Hazelcast as JCache provider, please check the official Hazelcast documentation: Hazelcast JCache.