MapReduce实现推荐系统(3)

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;

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.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.RunningJob;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;

public class Step2 {
    public static class Step2_UserVectorToCooccurrenceMapper extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> {
        private final static Text k = new Text();
        private final static IntWritable v = new IntWritable(1);

        public void map(LongWritable key, Text values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
            String[] tokens = Recommend.DELIMITER.split(values.toString());
            for (int i = 1; i < tokens.length; i++) {
                String itemID = tokens[i].split(":")[0];
                for (int j = 1; j < tokens.length; j++) {
                    String itemID2 = tokens[j].split(":")[0];
                    k.set(itemID + ":" + itemID2);
                    output.collect(k, v);
                }
            }
        }
    }

public static class Step2_UserVectorToConoccurrenceReducer extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> {
        private IntWritable result = new IntWritable();

        public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
            int sum = 0;
            while (values.hasNext()) {
                sum += values.next().get();
            }
            result.set(sum);
            output.collect(key, result);
        }
    }

public static void run(Map<String, String> path) throws IOException {
        JobConf conf = Recommend.config();

String input = path.get("Step2Input");
        String output = path.get("Step2Output");

HdfsDAO hdfs = new HdfsDAO(Recommend.HDFS, conf);
        hdfs.rmr(output);

conf.setOutputKeyClass(Text.class);
        conf.setOutputValueClass(IntWritable.class);

conf.setMapperClass(Step2_UserVectorToCooccurrenceMapper.class);
//        conf.setCombinerClass(Step2_UserVectorToConoccurrenceReducer.class);
//        conf.setReducerClass(Step2_UserVectorToConoccurrenceReducer.class);

conf.setInputFormat(TextInputFormat.class);
        conf.setOutputFormat(TextOutputFormat.class);

FileInputFormat.setInputPaths(conf, new Path(input));
        FileOutputFormat.setOutputPath(conf, new Path(output));

RunningJob job = JobClient.runJob(conf);
        while (!job.isComplete()) {
            job.waitForCompletion();
        }
    }
}

Step2运行结果：