Thursday 24 December 2015
Input Data:
"0195153448";"Classical Mythology";"Mark P. O. Morford";"2002";"Oxford University Press";"http://images.amazon.com/images/P/0195153448.01.THUMBZZZ.jpg";"http://images.amazon.com/images/P/0195153448.01.MZZZZZZZ.jpg";"http://images.amazon.com/images/P/0195153448.01.LZZZZZZZ.jpg"
"0002005018";"Clara Callan";"Richard Bruce Wright";"2001";"HarperFlamingo Canada";"http://images.amazon.com/images/P/0002005018.01.THUMBZZZ.jpg";"http://images.amazon.com/images/P/0002005018.01.MZZZZZZZ.jpg";http://images.amazon.com/images/P/0002005018.01.LZZZZZZZ.jpg
Program:
package Books;
import java.io.IOException;
import java.util.Iterator;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
//import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;
public class BooksFrequency
{
public static class BooksXMapper extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable>
{
@Override
public void map(LongWritable key, Text value,
OutputCollector<Text, IntWritable> output, Reporter reporter)
throws IOException {
String temp = value.toString();
String[] SingleBookdata = temp.split("\";\"");
output.collect(new Text(SingleBookdata[3]),new IntWritable(1));
}
}
public static class BooksXReducer extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable>
{
@Override
public void reduce(Text key, Iterator<IntWritable> values,
OutputCollector<Text, IntWritable> output, Reporter reporter)
throws IOException {
int bookfreq = 0;
while(values.hasNext())
{
IntWritable value = (IntWritable)values.next();
bookfreq = bookfreq + value.get();
}
output.collect(key, new IntWritable(bookfreq));
}
}
public static void main(String[] args) throws Exception
{
JobConf newconf = new JobConf();
newconf.setJarByClass(BooksFrequency.class);
newconf.setJobName("bookfrequency");
newconf.setOutputKeyClass(Text.class);
newconf.setOutputValueClass(IntWritable.class);
newconf.setMapperClass(BooksXMapper.class);
newconf.setReducerClass(BooksXReducer.class);
//newconf.setCombinerClass(BooksXReducer.class);
newconf.setInputFormat(TextInputFormat.class);
newconf.setOutputFormat(TextOutputFormat.class);
FileInputFormat.setInputPaths(newconf, new Path(args[0]));
FileOutputFormat.setOutputPath(newconf, new Path(args[1]));
JobClient.runJob(newconf);
}
}
Output:
2002 – 1
2001 – 1
