kafka 简单安装以及java小demo
系统:centos7下载kafka:http://kafka.apache.org/downloads ,我下载的版本为 kafka_2.11-0.10.1.0.tgz 。安装ZooKeeper,默认已经安装好 zookeeper-3.4.9 并已经启动。第1步,下载解压 kafka:# tar -xzf kafka_2.11-0.10.1.0.tgz# cd kafka_
系统:centos7
下载kafka:http://kafka.apache.org/downloads ,我下载的版本为 kafka_2.11-0.10.1.0.tgz 。
安装ZooKeeper,默认已经安装好 zookeeper-3.4.9 并已经启动。
第1步,下载解压 kafka:
# tar -xzf kafka_2.11-0.10.1.0.tgz
# cd kafka_2.11-0.10.1.0
第2步,运行 kafka:
kafka的运行是需要ZooKeeper支持的,所以要先启动一个ZooKeeper,但是如果实在不想安装,只是为了小实验,那么kafka也提供了一个便捷的小脚本模拟ZooKeeper运行:
> bin/zookeeper-server-start.sh config/zookeeper.properties
这里我有自己单独的ZooKeeper。
root 59741 1 47 17:17 pts/2 00:00:06 /usr/local/java/jdk1.8.0_131/bin/java -Dzookeeper.log.dir=. -Dzookeeper.root.logger=INFO,CONSOLE -cp /usr/local/zookeeper-3.4.9/bin/../build/classes:/usr/local/zookeeper-3.4.9/bin/../build/lib/*.jar:/usr/local/zookeeper-3.4.9/bin/../lib/slf4j-log4j12-1.6.1.jar:/usr/local/zookeeper-3.4.9/bin/../lib/slf4j-api-1.6.1.jar:/usr/local/zookeeper-3.4.9/bin/../lib/netty-3.10.5.Final.jar:/usr/local/zookeeper-3.4.9/bin/../lib/log4j-1.2.16.jar:/usr/local/zookeeper-3.4.9/bin/../lib/jline-0.9.94.jar:/usr/local/zookeeper-3.4.9/bin/../zookeeper-3.4.9.jar:/usr/local/zookeeper-3.4.9/bin/../src/java/lib/*.jar:/usr/local/zookeeper-3.4.9/bin/../conf:.:/usr/local/java/jdk1.8.0_131/lib/dt.jar:/usr/local/java/jdk1.8.0_131/lib/tools.jar -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false org.apache.zookeeper.server.quorum.QuorumPeerMain /usr/local/zookeeper-3.4.9/bin/../conf/zoo.cfg
那么现在使用默认配置文件启动 kafka 的服务:
# /usr/local/kafka_2.11-0.10.1.0/bin/kafka-server-start.sh /usr/local/kafka_2.11-0.10.1.0/config/server.properties
然后会出现一堆默认的配置。。。最后一行再来个 INFO [Kafka Server 0], started (kafka.server.KafkaServer),就完成了。
第3步,创建topic
进入kafka根目录,创建一个单分区单分片名为“test”的topic。
# bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic test
Created topic "test".
然后执行topic的list命令时候,就会列出所有的topic:
# bin/kafka-topics.sh --list --zookeeper localhost:2181
test
或者,也可以配置broker的server.property中的auto.create.topics.enable = true,当不存在的主题被发布时,会自动创建该主题。默认是 true。
第4步,生产者发送消息
kafka 附带一个命令行客户端,它将从文件或标准输入中获取输入信息,并将其作为消息发送到 kafka 集群。默认情况下,每一行将作为一个单独的消息发送。
运行生产者程序并发送消息:
# bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test
helo^[[D^H2018
hello2018
第5步,消费者接收消息
# bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginning
he2018
hello2018
使用 java 客户端
在使用非本机连接的时候,最好先在 config/server.properties 里面把 listeners 修改一下,否则容易连接失败。
listeners=PLAINTEXT://10.10.22.0:9092
引入jar包
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka_2.12</artifactId>
<version>1.0.0</version>
</dependency>
生产者代码,每秒发送一条数据,topic 不存在会自动创建:
import org.apache.kafka.clients.producer.*;
import java.util.Properties;
public class KafkaProducerDemo {
private final Producer<String,String> kafkaProducer;
public final static String TOPIC="JAVA_TOPIC";
private KafkaProducerDemo(){
kafkaProducer=createKafkaProducer() ;
}
private Producer<String,String> createKafkaProducer(){
Properties props = new Properties();
props.put("bootstrap.servers", "10.10.22.0:9092");
props.put("acks", "all");
props.put("retries", 0);
props.put("batch.size", 16384);
props.put("linger.ms", 1);
props.put("buffer.memory", 33554432);
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
Producer<String, String> kafkaProducer = new KafkaProducer<>(props);
return kafkaProducer;
}
void produce(){
for(int i=1;i<1000;i++){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
String key=String.valueOf("key"+i);
String data="hello kafka message:"+key;
kafkaProducer.send(new ProducerRecord<>(TOPIC, key, data), new Callback() {
@Override
public void onCompletion(RecordMetadata recordMetadata, Exception e) {
//do sth
}
});
System.out.println(data);
}
}
public static void main(String[] args){
new KafkaProducerDemo().produce();
}
}
消费者类代码:
import kafka.consumer.ConsumerConfig;
import kafka.consumer.ConsumerIterator;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;
import kafka.serializer.StringDecoder;
import kafka.utils.VerifiableProperties;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import java.util.*;
public class KafkaConsumerDemo {
private final KafkaConsumer<String, String> consumer;
private KafkaConsumerDemo(){
Properties props = new Properties();
props.put("bootstrap.servers", "10.10.22.0:9092");
props.put("group.id", "test");
props.put("enable.auto.commit", "true");
props.put("auto.commit.interval.ms", "1000");
props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
consumer = new KafkaConsumer<>(props);
}
void consume(){
consumer.subscribe(Arrays.asList(KafkaProducerDemo.TOPIC));
while (true) {
ConsumerRecords<String, String> records = consumer.poll(100);
for (ConsumerRecord<String, String> record : records)
System.out.printf("offset = %d, key = %s, value = %s%n", record.offset(), record.key(), record.value());
}
}
public static void main(String[] args){
new KafkaConsumerDemo().consume();
}
}
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