Spring Boot集成kafka笔记

kafka官网 http://kafka.apache.org/quickstart

KafkaOffsetMonitor 开源web管理界面

spring-kafka当前稳定版本是1.2.0..RELEASE  http://docs.spring.io/spring-kafka/docs/1.2.0.RELEASE/reference/html/_introduction.html

 

1.首先下载kafka,解压缩,然后运行zookeeper和kafka

cd kafka_2.11-0.10.2.0

bin/zookeeper-server-start.sh config/zookeeper.properties

bin/kafka-server-start.sh config/server.properties

经过测试发现Java程序发送消息时自动创建了主题,所以不需要用命令单独创建主题了(如果用命令行producer来绑定主题topic必须要先用命令行创建一个topic)

 

2.按照spring-kafka官网集成文档

1)pom中添加依赖

 


    org.apache.kafka
    kafka-clients
    0.10.2.0


    org.springframework.kafka
    spring-kafka
    1.2.0.RELEASE

 

2)配置,spring boot1.5.1可以直接在application.yml 配置文件中配置,官方文档说只要配置两个必要项就可以了

 

spring:
  kafka:
    consumer:
      group-id: foo
      auto-offset-reset: earliest

group-id是所属分组(kafka要求一个分组的成员数量不能大于设置的分区数,否则同一个分组中多出的成员永远都不会收到消息),auto-offset-reset设为earliest是获取以前就有过的消息(其实不是必要的配置)

 

可以在配置文件中进行更完整的配置,但是配置文件中支持的默认配置项还是有限,如果需要更加完整的配置建议还是用bean配置

 

spring:
  kafka:
    producer:
      retries: 0
      batch-size: 16384
      buffer-memory: 33554432
      key-serializer: org.apache.kafka.common.serialization.StringSerializer
      value-serializer: org.apache.kafka.common.serialization.StringSerializer
      bootstrap-servers: localhost:9092
    consumer:
      bootstrap-servers: localhost:9092
      group-id: foo
      auto-offset-reset: earliest
      enable-auto-commit: true
      auto-commit-interval: 100
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

 

3.Java部分就是spring-kafka官网使用的代码粘贴过来了,可以直接在application中同时运行producer和consumer

import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.support.SpringBootServletInitializer;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.kafka.core.KafkaTemplate;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

@SpringBootApplication
@Slf4j
public class MyApplication extends SpringBootServletInitializer implements CommandLineRunner {

   @Override
   protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
      return application.sources(MyApplication.class);
   }

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

   @Autowired
   private KafkaTemplate template;

   private final CountDownLatch latch = new CountDownLatch(4);

   @Override
   public void run(String... args) throws Exception {
      this.template.send("myTopic", "foo1");
      this.template.send("myTopic", "foo2");
      this.template.send("myTopic", "foo3");
      this.template.send("myTopic", "hi", "foo4");
this.template.send("myTopic2", "2", "foo5");

latch.await(60, TimeUnit.SECONDS); log.info("All received"); } @KafkaListener(topics = "myTopic") public void listen(ConsumerRecord, ?> cr) throws Exception { log.info(cr.toString()); latch.countDown(); }}

 

可以发现发送消息非常简单,先自动注入一个template,然后template.send(主题,data)或者template.send(主题,key, data)即可

客户端consumer获取消息特别简单,直接用@KafkaListener注解即可,并在监听中设置监听的主题,topics是一个数组可以绑定多个主题的,上面的代码中修改为@KafkaListener(topics = {"myTopic","myTopic2"})就可以同时监听两个主题的消息了,但是需要注意的是开始监听主题前要求主题已经被创建好了。

 

4.上面只是程序创建producer和consumer,还可以在命令窗口发送消息和接受消息

 

bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic myTopic  --from-beginning

bin/kafka-console-producer.sh --broker-list localhost:9092 --topic myTopic

bin/kafka-console-producer.sh --broker-list localhost:9092 --topic myTopic2

在producer命令窗口发送消息,在consumer命令窗口和spring-boot程序中都可以接收到消息。注意的是用命令行创建的producer绑定的主题topic需要用命令行先创建topic,但是在前面的Java程序中已经发送过myTopic和myTopic2两个主题消息,主题已经被Java程序创建好了,所以这里就不需要创建了

 

demo源码下载http://git.oschina.net/liufang1991/kafkademo

 

 

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