import scala.Tuple2;

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 java.util.Arrays;

import java.util.List;

import java.util.regex.Pattern;

public final class WordCount {

    private static final Pattern SPACE = Pattern.compile(" ");

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

        SparkConf sparkConf = new SparkConf().setAppName("JavaWordCount");//关键是没有指定master，需要提交到集群上运行

        JavaSparkContext ctx = new JavaSparkContext(sparkConf);

        JavaRDD<String> lines = ctx.textFile("C:\\test.txt", 1);

        JavaRDD<String> words = lines.flatMap(new FlatMapFunction<String, String>() {

            public Iterable<String> call(String s) {

                return Arrays.asList(SPACE.split(s));

            }

        });

        JavaPairRDD<String, Integer> ones = words.mapToPair(new PairFunction<String, String, Integer>() {

            public Tuple2<String, Integer> call(String s) {

                return new Tuple2<String, Integer>(s, 1);

            }

        });

        JavaPairRDD<String, Integer> counts = ones.reduceByKey(new Function2<Integer, Integer, Integer>() {

            public Integer call(Integer i1, Integer i2) {

                return i1 + i2;

            }

        });

        List<Tuple2<String, Integer>> output = counts.collect();

        for (Tuple2<?,?> tuple : output) {

            System.out.println(tuple._1() + ": " + tuple._2());

        }

        ctx.stop();

    }

}