标签:框架 key mouse nbsp csdn configure 字符串 升级 序列
kafka只接收bytes字节数组,所以自定义序列化器内部实现需按照bytes字节数组转换为标准。
重点:本例子只是提供参考怎样写自定义序列化器,因为关系到性能,一般默认使用StringSerializer即可,效率很高。
小知识:Kafka支持Avro序列化器,比较适用于生产者和消费者在版本升级差距拉大时使用,但同时要注意性能。参考文章《使用kafka中提供的Avro序列化框架实现序列化》
1) 自定义序列化类,转换成bytes字节数组:
import cn.enjoyedu.vo.DemoUser; import org.apache.kafka.common.errors.SerializationException; import org.apache.kafka.common.serialization.Serializer; import java.nio.ByteBuffer; import java.util.Map; /** * @author King老师*/ public class MySerializer implements Serializer<DemoUser> { public void configure(Map<String, ?> configs, boolean isKey) { //do nothing } public byte[] serialize(String topic, DemoUser data) { try { byte[] name; int nameSize; if(data==null){ return null; } if(data.getName()!=null){ name = data.getName().getBytes("UTF-8"); //字符串的长度 nameSize = data.getName().length(); }else{ name = new byte[0]; nameSize = 0; } /*id的长度4个字节,字符串的长度描述4个字节, 字符串本身的长度nameSize个字节*/ ByteBuffer buffer = ByteBuffer.allocate(4+4+nameSize); buffer.putInt(data.getId());//4 buffer.putInt(nameSize);//4 buffer.put(name);//nameSize return buffer.array(); } catch (Exception e) { throw new SerializationException("Error serialize DemoUser:"+e); } } public void close() { //do nothing } }
2) 自定义反序列化类,从bytes字节数组转换成自定义对象:
import cn.enjoyedu.vo.DemoUser; import org.apache.kafka.common.errors.SerializationException; import org.apache.kafka.common.serialization.Deserializer; import java.nio.ByteBuffer; import java.util.Map; /** * @author King老师 */ public class MyDeserializer implements Deserializer<DemoUser> { public void configure(Map<String, ?> configs, boolean isKey) { //do nothing } public DemoUser deserialize(String topic, byte[] data) { try { if(data==null){ return null; } if(data.length<8){ throw new SerializationException("Error data size."); } ByteBuffer buffer = ByteBuffer.wrap(data); int id; String name; int nameSize; id = buffer.getInt(); nameSize = buffer.getInt(); byte[] nameByte = new byte[nameSize]; buffer.get(nameByte); name = new String(nameByte,"UTF-8"); return new DemoUser(id,name); } catch (Exception e) { throw new SerializationException("Error Deserializer DemoUser."+e); } } public void close() { //do nothing } }
3) 配置序列化类
定义好自定义数据序列化类,需配置到kafka的配置里(参考《kafka2.5.0生产者与消费者配置详解》):
ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, MySerializer.class
ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, MySerializer.class
end.
标签:框架 key mouse nbsp csdn configure 字符串 升级 序列
原文地址:https://www.cnblogs.com/zhuwenjoyce/p/13191550.html