Spark Streaming---Streaming Word Count(java)

package com.spark.streaming;import java.util.Arrays;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;public class StreamingWordcount {    // yum install nc    // nc -lk 8888    public static void main(String[] args) {        SparkConf conf = new SparkConf().setAppName("StreamingWordcount").setMaster("local[2]");        /*         * 创建该对象类似于spark core中的JavaSparkContext,类似于SparkSQL中SQLContext         * 该对象除了接受SparkConf对象,还接收一个BatchInterval参数,就是说,每收集多长时间的数据划分为一个Batch即RDD去执行         * 这里Durations可以设置分钟、毫秒、秒         */        JavaStreamingContext jssc = new JavaStreamingContext(conf, Durations.seconds(5)) ;        /*         * 首先创建输入DStream,代表一个数据源比如这里从socket或Kafka来持续不断的进入实时数据流         * 创建一个监听socket数据量,RDD里面的每一个元素就是一行行的文本         */        JavaReceiverInputDStream<String> lines = jssc.socketTextStream("node15", 8888);        JavaDStream<String> words = lines.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(" "));            }        });        JavaPairDStream<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 {                return new Tuple2<String,Integer>(word, 1);            }        });        JavaPairDStream<String, Integer> wordcounts = pairs.reduceByKey(new Function2<Integer, Integer, Integer>() {            private static final long serialVersionUID = 1L;            @Override            public Integer call(Integer v1, Integer v2) throws Exception {                return v1 + v2;            }        });        // 最后每次计算完成,都打印一下这5秒钟的单词统计情况        wordcounts.print();        jssc.start();        jssc.awaitTermination();        jssc.close();    }}