生成flink消费kafka数据,以orc格式写入到hdfs
时间: 2024-05-10 13:21:04 浏览: 205
以下是一个基于Flink消费Kafka数据并将其写入HDFS的示例:
```java
import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.formats.orc.OrcSplitReaderUtil;
import org.apache.flink.formats.orc.OrcWriterFactory;
import org.apache.flink.formats.orc.vector.StringColumnVector;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer;
import org.apache.flink.streaming.util.serialization.JSONKeyValueDeserializationSchema;
import org.apache.flink.table.api.EnvironmentSettings;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.table.descriptors.*;
import org.apache.flink.types.Row;
import java.util.Properties;
public class FlinkKafkaHdfsOrcDemo {
public static void main(String[] args) throws Exception {
// set up the streaming execution environment
final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1); // set parallelism to 1 for demo purposes
// set up the Kafka consumer properties
Properties kafkaProps = new Properties();
kafkaProps.setProperty("bootstrap.servers", "localhost:9092");
kafkaProps.setProperty("group.id", "flink-kafka-consumer-group");
// create a FlinkKafkaConsumer instance to consume Kafka data
FlinkKafkaConsumer<String> kafkaConsumer = new FlinkKafkaConsumer<>("my-topic", new SimpleStringSchema(), kafkaProps);
// create a data stream from the Kafka source
DataStream<String> kafkaStream = env.addSource(kafkaConsumer);
// parse the JSON data and create a table from it
EnvironmentSettings settings = EnvironmentSettings.newInstance().inStreamingMode().useBlinkPlanner().build();
StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env, settings);
tableEnv.connect(new Kafka().version("universal").topic("my-topic").startFromEarliest().property("bootstrap.servers", "localhost:9092").property("group.id", "flink-kafka-consumer-group"))
.withFormat(new Json().deriveSchema())
.withSchema(new Schema().field("name", DataTypes.STRING()).field("age", DataTypes.INT()))
.createTemporaryTable("myTable");
Table myTable = tableEnv.from("myTable");
// create an OrcWriterFactory to write ORC data
OrcWriterFactory<Row> orcWriterFactory = (OrcWriterFactory<Row>) OrcSplitReaderUtil.createRowOrcWriterFactory(
new String[]{"name", "age"},
new OrcSplitReaderUtil.TypeDescription[]{
OrcSplitReaderUtil.TypeDescription.createString(),
OrcSplitReaderUtil.TypeDescription.createInt()
});
// create a FlinkKafkaProducer instance to write Kafka data
FlinkKafkaProducer<Row> kafkaProducer = new FlinkKafkaProducer<>(
"my-topic",
new OrcRowSerializationSchema("/path/to/hdfs/file.orc", orcWriterFactory),
kafkaProps,
FlinkKafkaProducer.Semantic.EXACTLY_ONCE);
// write the table data to HDFS in ORC format
myTable.execute().output(kafkaProducer);
// execute the job
env.execute("Flink Kafka HDFS ORC Demo");
}
// implementation of OrcRowSerializationSchema
private static class OrcRowSerializationSchema implements FlinkKafkaProducer.SerializationSchema<Row> {
private final String filePath;
private final OrcWriterFactory<Row> orcWriterFactory;
private transient OrcWriterFactory.Writer<Row> orcWriter;
public OrcRowSerializationSchema(String filePath, OrcWriterFactory<Row> orcWriterFactory) {
this.filePath = filePath;
this.orcWriterFactory = orcWriterFactory;
}
@Override
public byte[] serialize(Row row) {
try {
if (orcWriter == null) {
orcWriter = orcWriterFactory.createWriter(filePath, FileSystem.getHadoopFileSystem(new org.apache.flink.core.fs.Path(filePath).toUri()), true);
}
StringColumnVector nameVector = new StringColumnVector(1);
nameVector.vector[0] = row.getField(0).toString();
StringColumnVector ageVector = new StringColumnVector(1);
ageVector.vector[0] = row.getField(1).toString();
orcWriter.addRow(nameVector, ageVector);
return null;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
}
```
该示例使用Flink的Table API从Kafka消费数据,并将其写入HDFS中的ORC文件。示例代码使用`JsonKeyValueDeserializationSchema`解析JSON格式的数据,并使用`OrcWriterFactory`将数据写入ORC文件。在示例中,`OrcWriterFactory`被配置为使用String和Int类型的列。还创建了一个`OrcRowSerializationSchema`类,它将Flink的`Row`类型转换为ORC文件中的列向量,并使用`OrcWriterFactory.Writer`将数据写入ORC文件。
注意:在实际使用中,应该根据实际需求修改示例代码,并根据需要添加适当的错误处理和容错机制。
阅读全文