大数据技术与架构
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canal-kafka是阿里云最近更新的一个新的安装包。主要功能是实现canal与kafka的对接，实现海量的消息传输同步。在canal-kafka中，消息是以ByteString进行传输的，并且用户只能通过配置来指定一些kafka的配置，从某种程度上有一定的局限性，所以我们使用canal来自定义客户端kafka，会有更好的灵活性，但维护成本会更大，所以如何选择根据实际情况而定。
构建maven依赖
<dependency>
<groupId>com.alibaba.otter</groupId>
<artifactId>canal.client</artifactId>
<version>1.0.25</version>
</dependency>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>1.1.0</version>
</dependency> SimpleCanalClient
package com.unigroup.client.canal;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.InetSocketAddress;
import java.util.List;
import com.alibaba.otter.canal.client.CanalConnector;
import com.alibaba.otter.canal.client.CanalConnectors;
import com.alibaba.otter.canal.protocol.CanalEntry.Entry;
import com.alibaba.otter.canal.protocol.Message;
import com.unigroup.core.canal.CanalToKG;
/**
* @Title: SimpleCanalClient.java
* @Package com.unigroup.canal
* @Description: canal单实例接口
*/
public class SimpleCanalClient {
private CanalConnector connector=null;
public SimpleCanalClient(String ip,String port,String instance) {
// 创建链接
connector = CanalConnectors.newSingleConnector(new InetSocketAddress(ip, Integer.parseInt(port)),instance, "", "");
}
public List<Entry> execute(int batchSize,Class<?> clazz ) throws InstantiationException, IllegalAccessException, NoSuchMethodException, SecurityException {
//int batchSize = 1;
int emptyCount = 0;
Object obj = clazz.newInstance();
Method method = clazz.getMethod("send",Message.class);
try {
connector.connect();
// connector.subscribe(".*\\..*");
connector.subscribe("test.test1");
connector.rollback();
int totalEmptyCount = 120;
while (emptyCount < totalEmptyCount) {
Message message = connector.getWithoutAck(batchSize); // 获取指定数量的数据
long batchId = message.getId();
int size = message.getEntries().size();
if (batchId == -1 || size == 0) {
emptyCount++;
System.out.println("empty count : " + emptyCount);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
} else {
emptyCount = 0;
method.invoke(obj, message);
}
connector.ack(batchId); // 提交确认
// connector.rollback(batchId); // 处理失败, 回滚数据
}
System.out.println("empty too many times, exit");
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
connector.disconnect();
}
return null;
}
} CanalKafkaProducer
package com.unigroup.kafka.producer;
import java.io.IOException;
import java.util.Properties;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringSerializer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.alibaba.otter.canal.protocol.Message;
import com.unigroup.kafka.producer.KafkaProperties.Topic;
import com.unigroup.utils.MessageSerializer;
/**
* @Title: CanalKafkaProducer.java
* @Package com.unigroup.kafka.producer
* @version V1.0
*/
public class CanalKafkaProducer {
private static final Logger logger = LoggerFactory.getLogger(CanalKafkaProducer.class);
private Producer<String, Message> producer;
public void init(KafkaProperties kafkaProperties) {
Properties properties = new Properties();
properties.put("bootstrap.servers", kafkaProperties.getServers());
properties.put("acks", "all");
properties.put("retries", kafkaProperties.getRetries());
properties.put("batch.size", kafkaProperties.getBatchSize());
properties.put("linger.ms", kafkaProperties.getLingerMs());
properties.put("buffer.memory", kafkaProperties.getBufferMemory());
properties.put("key.serializer", StringSerializer.class.getName());
properties.put("value.serializer", MessageSerializer.class.getName());
producer = new KafkaProducer<String, Message>(properties);
}
public void stop() {
try {
logger.info("## stop the kafka producer");
producer.close();
} catch (Throwable e) {
logger.warn("##something goes wrong when stopping kafka producer:", e);
} finally {
logger.info("## kafka producer is down.");
}
}
public void send(Topic topic, Message message) throws IOException {
ProducerRecord<String, Message> record;
if (topic.getPartition() != null) {
record = new ProducerRecord<String, Message>(topic.getTopic(), topic.getPartition(), null, message);
} else {
record = new ProducerRecord<String, Message>(topic.getTopic(), message);
}
producer.send(record);
if (logger.isDebugEnabled()) {
logger.debug("send message to kafka topic: {} \n {}", topic.getTopic(), message.toString());
}
}
}
canalToKafkaServer
package com.unigroup.kafka.server;
import com.unigroup.client.canal.SimpleCanalClient;
import com.unigroup.kafka.producer.CanalKafkaProducer;
import com.unigroup.utils.GetProperties;
/**
* @Title: canal.java
* @Package com.unigroup.kafka.server
* @version V1.0
*/
public class canalToKafkaServer {
public static void execute() {
SimpleCanalClient simpleCanalClient = new SimpleCanalClient(GetProperties.getValue("MYSQL_HOST"),
GetProperties.getValue("MTSQL_PORT"), GetProperties.getValue("INSTANCE"));
try {
simpleCanalClient.execute(1,CanalKafkaProducer.class);
} catch (Exception e) {
e.printStackTrace();
}
}
}
至此一个简单的canal到kafka的demo已经完成。这些都只是测试代码，实际应用中根据不同的情况，可以自己开发更多功能。
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