Kafka是由LinkedIn开发的一个分布式的消息系统，使用Scala编写，它以可水平扩展和高吞吐率而被广泛使用。
Kafka.png
快速入门
maven依赖
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>0.9.0.0</version>
</dependency>
生产者
package com.bytebeats.mq.kafka;
import java.io.IOException;
import java.util.Properties;
import com.bytebeats.mq.kafka.util.PropertyUtils;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
public class KafkaProducerDemo {
private int total = 1000000;
public void send(){
long start = System.currentTimeMillis();
System.out.println("Kafka Producer send msg start,total msgs:"+total);
// set up the producer
Producer<String, String> producer = null;
try {
Properties props = PropertyUtils.load("producer_config.properties");
producer = new KafkaProducer<>(props);
for (int i = 0; i < total; i++){
producer.send(new ProducerRecord<String, String>("hello",
String.valueOf(i), String.format("{\"type\":\"test\", \"t\":%d, \"k\":%d}", System.currentTimeMillis(), i)));
// every so often send to a different topic
if (i % 1000 == 0) {
producer.send(new ProducerRecord<String, String>("test", String.format("{\"type\":\"marker\", \"t\":%d, \"k\":%d}", System.currentTimeMillis(), i)));
producer.send(new ProducerRecord<String, String>("hello", String.format("{\"type\":\"marker\", \"t\":%d, \"k\":%d}", System.currentTimeMillis(), i)));
producer.flush();
System.out.println("Sent msg number " + i);
}
}
} catch (IOException e) {
e.printStackTrace();
}finally{
producer.close();
}
System.out.println("Kafka Producer send msg over,cost time:"+(System.currentTimeMillis()-start)+"ms");
}
}
producer_config.properties
bootstrap.servers=172.18.19.206:9092,172.18.19.207:9092,172.18.19.208:9092
acks=all
retries=0
batch.size=16384
linger.ms=1
buffer.memory=33554432
auto.commit.interval.ms=1000
key.serializer=org.apache.kafka.common.serialization.StringSerializer
value.serializer=org.apache.kafka.common.serialization.StringSerializer
消费者
package com.bytebeats.mq.kafka;
import java.io.IOException;
import java.util.Arrays;
import java.util.Properties;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.bytebeats.mq.kafka.util.PropertyUtils;
public class KafkaConsumerDemo {
public void consume() {
JsonParser jsonParser = new JsonParser();
// and the consumer
KafkaConsumer<String, String> consumer = null;
try {
Properties props = PropertyUtils.load("consumer_config.properties");
consumer = new KafkaConsumer<>(props);
//subscribe topics
consumer.subscribe(Arrays.asList("hello", "test"));
while (true) {
ConsumerRecords<String, String> records = consumer.poll(100);
for (ConsumerRecord<String, String> record : records){
// System.out.printf("offset -> %d, key -> %s, value -> %s",
// record.offset(), record.key(), record.value());
switch (record.topic()) {
case "hello":
JsonObject jObj = (JsonObject)jsonParser.parse(record.value());
switch (jObj.get("type").getAsString()) {
case "test":
long latency = System.currentTimeMillis() - jObj.get("t").getAsLong();
System.out.println(latency);
break;
case "marker":
break;
default:
break;
}
break;
case "test":
break;
default:
throw new IllegalStateException("Shouldn't be possible to get message on topic " + record.topic());
}
}
}
} catch (IOException e) {
e.printStackTrace();
}finally{
if(consumer!=null){
consumer.close();
}
}
}
}
consumer_config.properties
bootstrap.servers=172.18.19.206:9092,172.18.19.207:9092,172.18.19.208:9092
group.id=test
enable.auto.commit=true
auto.commit.interval.ms=1000
session.timeout.ms=30000
key.deserializer=org.apache.kafka.common.serialization.StringDeserializer
value.deserializer=org.apache.kafka.common.serialization.StringDeserializer
PropertyUtils
package com.bytebeats.mq.kafka.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
public class PropertyUtils {
private PropertyUtils(){
}
public static Properties load(File file) throws IOException{
InputStream in = null;
try {
in = new FileInputStream(file);
Properties props = new Properties();
props.load(in);
return props;
}finally{
IoUtils.closeQuietly(in);
}
}
public static Properties load(String path) throws IOException{
InputStream in = null;
try {
in = PropertyUtils.class.getClassLoader().getResourceAsStream(path);
Properties props = new Properties();
props.load(in);
return props;
}finally{
IoUtils.closeQuietly(in);
}
}
}
源码下载
https://github.com/TiFG/mq-in-action/tree/master/kafka-sample
