Merge pull request #11597 from hcxin:master

* pr/11597:
  Polish "Add Kafka sample"
  Add Kafka sample

spring-boot-samples/README.adoc

@@ -119,6 +119,9 @@ The following sample applications are provided:
 | link:spring-boot-sample-junit-jupiter[spring-boot-sample-junit-jupiter]
 | Demonstrates JUnit Jupiter-based testing
 
+| link:spring-boot-sample-kafka[spring-boot-sample-kafka]
+| consumer and producer using Apache Kafka
+
 | link:spring-boot-sample-liquibase[spring-boot-sample-liquibase]
 | Database migrations with Liquibase
 

spring-boot-samples/pom.xml

@@ -57,6 +57,7 @@
 		<module>spring-boot-sample-jta-narayana</module>
 		<module>spring-boot-sample-jta-jndi</module>
 		<module>spring-boot-sample-junit-jupiter</module>
+		<module>spring-boot-sample-kafka</module>
 		<module>spring-boot-sample-liquibase</module>
 		<module>spring-boot-sample-logback</module>
 		<module>spring-boot-sample-oauth2-client</module>

spring-boot-samples/spring-boot-sample-kafka/pom.xml

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<!-- Your own application should inherit from spring-boot-starter-parent -->
+		<artifactId>spring-boot-samples</artifactId>
+		<groupId>org.springframework.boot</groupId>
+		<version>${revision}</version>
+	</parent>
+	<artifactId>spring-boot-sample-kafka</artifactId>
+	<name>Spring Boot Kafka Sample</name>
+	<description>Spring Boot Kafka Sample</description>
+
+	<properties>
+		<main.basedir>${basedir}/../..</main.basedir>
+	</properties>
+
+	<dependencies>
+		<!-- Compile -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-json</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.kafka</groupId>
+			<artifactId>spring-kafka</artifactId>
+		</dependency>
+		<!-- Test -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.kafka</groupId>
+			<artifactId>spring-kafka-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+</project>

spring-boot-samples/spring-boot-sample-kafka/src/main/java/sample/kafka/Consumer.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sample.kafka;
+
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.stereotype.Component;
+
+@Component
+class Consumer {
+
+	@KafkaListener(topics = "testTopic")
+	public void processMessage(SampleMessage message) {
+		System.out.println("Received sample message [" + message + "]");
+	}
+
+}

spring-boot-samples/spring-boot-sample-kafka/src/main/java/sample/kafka/Producer.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sample.kafka;
+
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.stereotype.Component;
+
+@Component
+public class Producer {
+
+	private final KafkaTemplate<Object, SampleMessage> kafkaTemplate;
+
+	Producer(KafkaTemplate<Object, SampleMessage> kafkaTemplate) {
+		this.kafkaTemplate = kafkaTemplate;
+	}
+
+	public void send(SampleMessage message) {
+		this.kafkaTemplate.send("testTopic", message);
+		System.out.println("Sent sample message [" + message + "]");
+	}
+
+}

spring-boot-samples/spring-boot-sample-kafka/src/main/java/sample/kafka/SampleKafkaApplication.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sample.kafka;
+
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class SampleKafkaApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SampleKafkaApplication.class, args);
+	}
+
+	@Bean
+	public ApplicationRunner runner(Producer producer) {
+		return args -> producer.send(new SampleMessage(1, "A simple test message"));
+	}
+
+}

spring-boot-samples/spring-boot-sample-kafka/src/main/java/sample/kafka/SampleMessage.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sample.kafka;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class SampleMessage {
+
+	private final Integer id;
+
+	private final String message;
+
+	@JsonCreator
+	public SampleMessage(@JsonProperty("id") Integer id,
+			@JsonProperty("message") String message) {
+		this.id = id;
+		this.message = message;
+	}
+
+	public Integer getId() {
+		return this.id;
+	}
+
+	public String getMessage() {
+		return this.message;
+	}
+
+	@Override
+	public String toString() {
+		final StringBuilder sb = new StringBuilder("SampleMessage{");
+		sb.append("id=").append(this.id);
+		sb.append(", message='").append(this.message).append('\'');
+		sb.append('}');
+		return sb.toString();
+	}
+
+}

spring-boot-samples/spring-boot-sample-kafka/src/main/resources/application.properties

@@ -0,0 +1,6 @@
+spring.kafka.bootstrap-servers=localhost:9092
+spring.kafka.consumer.group-id=testGroup
+spring.kafka.consumer.auto-offset-reset=earliest
+spring.kafka.consumer.value-deserializer=org.springframework.kafka.support.serializer.JsonDeserializer
+spring.kafka.producer.value-serializer=org.springframework.kafka.support.serializer.JsonSerializer
+spring.kafka.consumer.properties.spring.json.trusted.packages=sample.kafka

spring-boot-samples/spring-boot-sample-kafka/src/test/java/sample/kafka/SampleKafkaApplicationTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sample.kafka;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.boot.test.rule.OutputCapture;
+import org.springframework.context.annotation.Bean;
+import org.springframework.kafka.test.context.EmbeddedKafka;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for demo application.
+ *
+ * @author hcxin
+ * @author Gary Russell
+ * @author Stephane Nicoll
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@TestPropertySource(properties = "spring.kafka.bootstrap-servers=${spring.embedded.kafka.brokers}")
+@EmbeddedKafka
+public class SampleKafkaApplicationTests {
+
+	private static final CountDownLatch latch = new CountDownLatch(1);
+
+	@Rule
+	public OutputCapture outputCapture = new OutputCapture();
+
+	@Test
+	public void testVanillaExchange() throws Exception {
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(this.outputCapture.toString().contains("A simple test message"))
+				.isTrue();
+	}
+
+	@TestConfiguration
+	public static class Config {
+
+		@Bean
+		public Consumer consumer() {
+			return new Consumer() {
+				@Override
+				public void processMessage(SampleMessage message) {
+					super.processMessage(message);
+					latch.countDown();
+				}
+			};
+		}
+
+	}
+
+}