apache hadoop sequence file reader - Java Big Data

Java examples for Big Data:Hadoop

  1. HOME
  2. Java
  3. Big Data
  4. Hadoop

Description

apache hadoop sequence file reader

Demo Code

package Hdfs;/*from  w  w  w  .  j a v  a  2 s . c  om*/

import java.io.IOException;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.util.ReflectionUtils;

public class SequenceFileReader {

    public static void main(String[] args) {
        String uri = "hdfs://neusoft-master:9000/user/root/test/demo1";
        Configuration conf = new Configuration();
        SequenceFile.Reader reader = null;
        try {
            FileSystem fs = FileSystem.get(URI.create(uri), conf);
            Path path = new Path(uri);
            reader = new SequenceFile.Reader(fs, path, conf);
            Writable key = (Writable) ReflectionUtils.newInstance(
                    reader.getKeyClass(), conf);
            Writable value = (Writable) ReflectionUtils.newInstance(
                    reader.getValueClass(), conf);
            long position = reader.getPosition();
            while (reader.next(key, value)) {
                System.out.printf("[%s]\t%s\n", key, value);
                position = reader.getPosition();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            IOUtils.closeStream(reader);
        }

    }
}

Related Tutorials