安裝nc： yum install nc

WordCount

package cn.spark.streaming;

import java.util.Arrays;
import java.util.Iterator;

import org.apache.spark.SparkConf;
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.streaming.Durations;
import org.apache.spark.streaming.api.java.JavaDStream;
import org.apache.spark.streaming.api.java.JavaPairDStream;
import org.apache.spark.streaming.api.java.JavaReceiverInputDStream;
import org.apache.spark.streaming.api.java.JavaStreamingContext;

import scala.Tuple2;

/**
 * 基于 scoket的wordcount程序
 * @author ThinkVision
 *
 */
public class WordCount {

    public static void main(String[] args) throws Exception {
        
        SparkConf conf = new SparkConf().setAppName("WordCount");
        
        JavaStreamingContext jssc = new JavaStreamingContext(conf, Durations.seconds(1));
        
        // create InputDStream
        JavaReceiverInputDStream<String> lineInputDStream = jssc.socketTextStream("hserver-1", 9999);
        
        // transform lineInputDStream into wordDStream
        JavaDStream<String> wordDStream = lineInputDStream.flatMap(
                
                new FlatMapFunction<String, String>() {

                    private static final long serialVersionUID = 425086794973670380L;
        
                    @Override
                    public Iterator<String> call(String line) throws Exception {
                        
                        return Arrays.asList(line.split(" ")).iterator();
                    }
                });
        
        // transform wordDStream into pairDStream
        JavaPairDStream<String, Integer> pairDStream = wordDStream.mapToPair(
                
                new PairFunction<String, String, Integer>() {

                    private static final long serialVersionUID = -7388596223277641539L;

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

                        return new Tuple2<String, Integer>(word, 1);
                    }
                });
        
        
        // reduceByKey
        JavaPairDStream<String, Integer> resultDStream = pairDStream.reduceByKey(
                
                new Function2<Integer, Integer, Integer>() {
                    
                    private static final long serialVersionUID = 5957698719526594872L;

                    @Override
                    public Integer call(Integer v1, Integer v2) throws Exception {

                        return v1 + v2;
                    }
                });
        
        resultDStream.print();
        
        jssc.start();
        
        jssc.awaitTermination();
        
        jssc.close();
        
    }
}