import java.util.Arrays;

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 org.apache.spark.api.java.function.VoidFunction;

import scala.Tuple2;

public class WordCount {

    public static void main(String[] args) {

        SparkConf conf = new SparkConf().setMaster("local").setAppName("wc");

        JavaSparkContext sc = new JavaSparkContext(conf);

        JavaRDD<String> text = sc.textFile("hdfs://master:9000/user/hadoop/input/test");

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

            private static final long serialVersionUID = 1L;

            @Override

            public Iterable<String> call(String line) throws Exception {

                return Arrays.asList(line.split(" "));//把字符串转化成list

            }

        });

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

            private static final long serialVersionUID = 1L;

            @Override

            public Tuple2<String, Integer> call(String word) throws Exception {

                // TODO Auto-generated method stub

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

            }

        });

        JavaPairRDD<String, Integer> results = pairs.reduceByKey(new Function2<Integer, Integer, Integer>() {

            private static final long serialVersionUID = 1L;

            @Override

            public Integer call(Integer value1, Integer value2) throws Exception {

                // TODO Auto-generated method stub

                return value1 + value2;

            }

        });

        JavaPairRDD<Integer, String> temp = results.mapToPair(new PairFunction<Tuple2<String,Integer>, Integer, String>() {

            private static final long serialVersionUID = 1L;

            @Override

            public Tuple2<Integer, String> call(Tuple2<String, Integer> tuple)

                    throws Exception {

                return new Tuple2<Integer, String>(tuple._2, tuple._1);

            }

        });

        JavaPairRDD<String, Integer> sorted = temp.sortByKey(false).mapToPair(new PairFunction<Tuple2<Integer,String>, String, Integer>() {

            private static final long serialVersionUID = 1L;

            @Override

            public Tuple2<String, Integer> call(Tuple2<Integer, String> tuple)

                    throws Exception {

                // TODO Auto-generated method stub

                return new Tuple2<String, Integer>(tuple._2,tuple._1);

            }

        });

        sorted.foreach(new VoidFunction<Tuple2<String,Integer>>() {

            private static final long serialVersionUID = 1L;

            @Override

            public void call(Tuple2<String, Integer> tuple) throws Exception {

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

            }

        });

        sc.close();

    }

}

 Look! at the window there leans an old maid. She plucks the  

withered leaf from the balsam, and looks at the grass-covered rampart,  

on which many children are playing. What is the old maid thinking  

of? A whole life drama is unfolding itself before her inward gaze.  

    "The poor little children, how happy they are- how merrily they  

play and romp together! What red cheeks and what angels' eyes! but  

they have no shoes nor stockings. They dance on the green rampart,  

just on the place where, according to the old story, the ground always  

sank in, and where a sportive, frolicsome child had been lured by  

means of flowers, toys and sweetmeats into an open grave ready dug for  

it, and which was afterwards closed over the child; and from that  

moment, the old story says, the ground gave way no longer, the mound  

remained firm and fast, and was quickly covered with the green turf.  

The little people who now play on that spot know nothing of the old  

tale, else would they fancy they heard a child crying deep below the  

earth, and the dewdrops on each blade of grass would be to them  

tears of woe. Nor do they know anything of the Danish King who here,  

in the face of the coming foe, took an oath before all his trembling  

courtiers that he would hold out with the citizens of his capital, and  

die here in his nest; they know nothing of the men who have fought  

here, or of the women who from here have drenched with boiling water  

the enemy, clad in white, and 'biding in the snow to surprise the  

city.  

.