spark wordcount—IDEA

package com.admin;

import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.FlatMapFunction;
import org.apache.spark.api.java.function.Function2;
import org.apache.spark.api.java.function.PairFunction;
import scala.Tuple2;

import java.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;

public final class JavaWordCount {
    private static final Pattern SPACE = Pattern.compile(" ");

    public static void main(String[] args) throws Exception {

        if (args.length < 1) {
            System.err.println("Usage: JavaWordCount ");
            System.exit(1);
        }

        SparkConf sparkConf = new SparkConf().setAppName("JavaWordCount");
        JavaSparkContext ctx = new JavaSparkContext(sparkConf);
        JavaRDD lines = ctx.textFile(args[0], 1);

        JavaRDD words = lines.flatMap(new FlatMapFunction() {
            @Override
            public Iterable call(String s) {
                return Arrays.asList(SPACE.split(s));
            }
        });

        JavaPairRDD ones = words.mapToPair(new PairFunction() {
            @Override
            public Tuple2 call(String s) {
                return new Tuple2(s, 1);
            }
        });

        JavaPairRDD counts = ones.reduceByKey(new Function2() {
            @Override
            public Integer call(Integer i1, Integer i2) {
                return i1 + i2;
            }
        });

        List> output = counts.collect();
        for (Tuple2 tuple : output) {
            System.out.println(tuple._1() + ": " + tuple._2());
        }
        ctx.stop();
    }
}