How to realize MAP for counting the number of input lines by hadoop

This article is about how hadoop implements MAP to count the number of input lines. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Import java.io.IOException;import java.util.regex.Matcher;import java.util.regex.Pattern;import org.apache.hadoop.io.LongWritable;import org.apache.hadoop.io.Text;import org.apache.hadoop.mapreduce.Mapper;public class FilterCidMap2 extends Mapper {private long count=0 @ Override protected void map (LongWritable key, Text value, Mapper.Context context) throws IOException, InterruptedException {try {/ / get the number of rows read count=key.get () / / normal logic context.write (new Text (), new LongWritable (1));} catch (Exception e) {e.printStackTrace () }} / / @ Override protected void cleanup (Mapper.Context context) throws IOException called after the map method is called, InterruptedException {/ / map cleans up the resource operation / / just take the linescount out of the reduce (new Text ("linesCount") New LongWritable (count)) Thank you for your reading! On "hadoop how to achieve statistical input lines of MAP," this article is shared here, I hope the above content can be of some help to you, so that you can learn more knowledge, if you think the article is good, you can share it out for more people to see it!