Java – reducer and MapReduce do not display errors, but do not provide the required output
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Java
Sales driver class
package mr.map; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.FloatWritable; //import org.apache.hadoop.mapreduce.Mapper; //import org.apache.hadoop.mapreduce.Reducer; public class SalesDriver { public static void main(String args[]) throws Exception { Configuration c=new Configuration(); Job j=new Job(c,"Sales"); j.setJarByClass(SalesDriver.class); j.setMapperClass(SalesMapper.class); j.setReducerClass(SalesReducer.class); //j.setNumReduceTasks(0); j.setOutputKeyClass(Text.class); j.setOutputValueClass(FloatWritable.class); Path in=new Path(args[0]); Path out=new Path(args[1]); FileInputFormat.addInputPath(j,in); FileOutputFormat.setOutputPath(j,out); System.exit(j.waitForCompletion(true)?0:1); } }
Sales mapper class
package mr.map; import java.io.IOException; //import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.FloatWritable; import org.apache.hadoop.io.LongWritable; //import org.apache.hadoop.io.DoubleWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Mapper; public class SalesMapper extends Mapper<LongWritable,Text,FloatWritable> { public void map(LongWritable k,Text v,Context con) throws IOException,InterruptedException { String w[]=v.toString().split(" "); String product=w[3]; //String store=w[2]; //float cost=Integer.parseInt(w[4]); float costx = Float.parseFloat(w[4]); //String newline= product+","+store; //","+costx; //String newline = product; con.write(new Text(product),new FloatWritable(costx)); } }
Sales of reducer
package mr.map; import java.io.IOException; import org.apache.hadoop.io.FloatWritable; //import org.apache.hadoop.io.IntWritable; //import org.apache.hadoop.io.DoubleWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Reducer; public class SalesReducer extends Reducer<Text,FloatWritable,FloatWritable> { public void reduce(Text k,Iterable<FloatWritable>vlist,InterruptedException { int tot=0; for (FloatWritable v:vlist) { tot += v.get(); } //int total= (int)tot; con.write(new Text(k),new FloatWritable(tot)); } }
MapReduce results
I can't understand why all the results appear near a large floating point number and all the numbers 5.7480884e7
The following is an example of input to the MapReduce program:
2012-01-01 09:00 San Jose Men's Clothing 214.05 Amex 2012-01-01 09:00 Fort Worth Women's Clothing 153.57 Visa 2012-01-01 09:00 San Diego Music 66.08 Cash 2012-01-01 09:00 Pittsburgh Pet Supplies 493.51 Discover 2012-01-01 09:00 Omaha Children's Clothing 235.63 MasterCard 2012-01-01 09:00 Stockton Men's Clothing 247.18 MasterCard 2012-01-01 09:00 Austin Cameras 379.6 Visa 2012-01-01 09:00 New York Consumer Electronics 296.8 Cash 2012-01-01 09:00 Corpus Christi Toys 25.38 Discover 2012-01-01 09:00 Fort Worth Toys 213.88 Visa 2012-01-01 09:00 Las Vegas Video Games 53.26 Visa 2012-01-01 09:00 Newark Video Games 39.75 Cash 2012-01-01 09:00 Austin Cameras 469.63 MasterCard 2012-01-01 09:00 Greensboro DVDs 290.82 MasterCard 2012-01-01 09:00 San Francisco Music 260.65 Discover 2012-01-01 09:00 Lincoln Garden 136.9 Visa 2012-01-01 09:00 Buffalo Women's Clothing 483.82 Visa 2012-01-01 09:00 San Jose Women's Clothing 215.82 Cash 2012-01-01 09:00 Boston Cameras 418.94 Amex 2012-01-01 09:00 Houston Baby 309.16 Visa 2012-01-01 09:00 Las Vegas Books 93.39 Visa 2012-01-01 09:00 Virginia Beach Children's Clothing 376.11 Amex 2012-01-01 09:01 Riverside Consumer Electronics 252.88 Cash 2012-01-01 09:01 Tulsa Baby 205.06 Visa 2012-01-01 09:01 Reno Crafts 88.25 Visa 2012-01-01 09:01 Chicago Books 31.08 Cash 2012-01-01 09:01 Fort Wayne Men's Clothing 370.55 Amex 2012-01-01 09:01 San Bernardino Consumer Electronics 170.2 Cash 2012-01-01 09:01 Madison Men's Clothing 16.78 Visa 2012-01-01 09:01 Austin Sporting Goods 327.75 Discover 2012-01-01 09:01 Portland CDs 108.69 Amex 2012-01-01 09:01 Riverside Sporting Goods 15.41 Discover 2012-01-01 09:01 Reno Toys 80.46 Visa 2012-01-01 09:01 Anchorage Music 298.86 MasterCard
Solution
You store the value of a floating point number in an int variable
Try changing the tot variable from int to float or double
double tot=0;
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