This version is still in development and is not considered stable yet. For the latest stable version, please use spring-cloud-stream 4.1.3!spring-doc.cn

This version is still in development and is not considered stable yet. For the latest stable version, please use spring-cloud-stream 4.1.3!spring-doc.cn

Preface

This section goes into more detail about how you can work with Spring Cloud Stream. It covers topics such as creating and running stream applications.spring-doc.cn

Introducing Spring Cloud Stream

Spring Cloud Stream is a framework for building message-driven microservice applications. Spring Cloud Stream builds upon Spring Boot to create standalone, production-grade Spring applications and uses Spring Integration to provide connectivity to message brokers. It provides opinionated configuration of middleware from several vendors, introducing the concepts of persistent publish-subscribe semantics, consumer groups, and partitions.spring-doc.cn

By adding spring-cloud-stream dependencies to the classpath of your application, you get immediate connectivity to a message broker exposed by the provided spring-cloud-stream binder (more on that later), and you can implement your functional requirement, which is run (based on the incoming message) by a java.util.function.Function.spring-doc.cn

The following listing shows a quick example:spring-doc.cn

@SpringBootApplication
public class SampleApplication {

	public static void main(String[] args) {
		SpringApplication.run(SampleApplication.class, args);
	}

    @Bean
	public Function<String, String> uppercase() {
	    return value -> value.toUpperCase();
	}
}

The following listing shows the corresponding test:spring-doc.cn

@SpringBootTest(classes =  SampleApplication.class)
@EnableTestBinder
class BootTestStreamApplicationTests {

	@Autowired
	private InputDestination input;

	@Autowired
	private OutputDestination output;

	@Test
	void contextLoads() {
		input.send(new GenericMessage<byte[]>("hello".getBytes()));
		assertThat(output.receive().getPayload()).isEqualTo("HELLO".getBytes());
	}
}

Main Concepts

Spring Cloud Stream provides a number of abstractions and primitives that simplify the writing of message-driven microservice applications. The rest of this reference manual provides additional details.spring-doc.cn

Section Summary