Flink 흐름 처리 입문 (자바)

package com.heiheihei.flink;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.java.utils.ParameterTool;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.time.Time;

/**
 * @author    1212
 * @version 1.0
 * @date 2020/3/31 17:22
 */
public class SocketWindowWordCount {
    public static void main(String[] args) throws Exception {
        //      
        int port = 8081;
        try {
            //       
            final ParameterTool params = ParameterTool.fromArgs(args);
            port = params.getInt("port");
        } catch (Exception e) {
            System.err.println("No port specified. Please run 'SocketWindowWordCount --port");
        }
        //    
        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        //    
        DataStream text = env.socketTextStream("localhost", port, "
");
        //    
        DataStream<WordWithCount> windowCounts = text.flatMap((FlatMapFunction<String, WordWithCount>) (s, collector) -> {
            for (String word : s.split(" ")) {
                collector.collect(new WordWithCount(word, 1L));
            }
        });
        //         
        windowCounts.keyBy("word")
                .timeWindow(Time.seconds(5), Time.seconds(1))
                .reduce(new ReduceFunction<WordWithCount>() {
                    @Override
                    public WordWithCount reduce(WordWithCount wordWithCount, WordWithCount t1) throws Exception {
                        return new WordWithCount(wordWithCount.word, wordWithCount.count + t1.count);
                    }
                });
        windowCounts.print().setParallelism(1);
        env.execute("Soket Window WordCount");
    }

    public static class WordWithCount {
        public String word;
        public long count;

        public WordWithCount() {
        }

        public WordWithCount(String word, long count) {
            this.word = word;
            this.count = count;
        }

        @Override
        public String toString() {
            return "WordWithCount{" +
                    "word='" + word + '\'' +
                    ", count=" + count +
                    '}';
        }
    }

}