一、消息队列场景

1.1、异步 

 1.2、解耦

 1.3、削峰

1.4、缓冲

二、springboot整合kafka

 导入pom依赖

<dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>
        </dependency>

 修改配置

spring.kafka.bootstrap-servers=192.168.200.1:9092
#配置序列化
spring.kafka.producer.value-serializer=org.springframework.kafka.support.serializer.JsonSerializer

发送消息：

@SpringBootTest
class Boot3KafkaApplicationTests {
    @Autowired
    private KafkaTemplate kafkaTemplate;
    @Test
    void contextLoads() {
        //计时
        StopWatch stopWatch = new StopWatch();
        CompletableFuture[] completableFuture = new CompletableFuture[1000];
        stopWatch.start();
        for (int i = 0; i < 1000; i++) {
            CompletableFuture send = kafkaTemplate.send("timi", "timi1", "haha");
            completableFuture[i] = send;
        }
        CompletableFuture.allOf(completableFuture).join();
        stopWatch.stop();
        //统计花费时间
        long totalTimeMillis = stopWatch.getTotalTimeMillis();
        System.out.println("1000条消息发送时间:"+ totalTimeMillis);
    }
    @Test
    void testKafka(){
        Person person = new Person();
        person.setName("张三");
        person.setAge(12);
        CompletableFuture send = kafkaTemplate.send("timi", "person", person);
        send.join();
    }
}

 创建主题

@Configuration
public class KafkaConfig {
    //创建主题
    @Bean
    public NewTopic topic(){
        return TopicBuilder.name("ax")
                .partitions(1)
                .compact()
                .build();
    }
}

获取消息

@Component
@Log4j2
public class TimiKafkaListener {
    //默认获取最后一条消息
    @KafkaListener(topics = "timi",groupId = "timi")
    public void timiKafka(ConsumerRecord record){
        Object key = record.key();
        Object value = record.value();
        log.info("接收到消息的key {}，value：{}",key,value);
    }
    //获取所有消息
    @KafkaListener(groupId = "ya",topicPartitions = {
            @TopicPartition(topic = "timi",partitionOffsets = {
                    @PartitionOffset(partition = "0",initialOffset = "0")
            })
    })
    public void timiKafka2(ConsumerRecord record){
        Object key = record.key();
        Object value = record.value();
        log.info("接收到消息的key2 {}，value2：{}",key,value);
    }
}