flink1.18传统流处理环境编写

package com.xiaohu.wc;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.util.Collector;

public class WordCountStreamDemo {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        DataStreamSource<String> lineDS = env.readTextFile("input/word.txt");

        lineDS.flatMap(new FlatMapFunction<String, Tuple2<String, Long>>() {
            @Override
            public void flatMap(String s, Collector<Tuple2<String, Long>> collector) throws Exception {
                String[] words = s.split(" ");
                for (String word : words) {
                    Tuple2<String, Long> tuple2 = Tuple2.of(word, 1L);
                    collector.collect(tuple2);
                }
            }
        }).keyBy(new KeySelector<Tuple2<String, Long>, String>() {
            @Override
            public String getKey(Tuple2<String, Long> stringLongTuple2) throws Exception {
                return stringLongTuple2.f0;
            }
        }).sum(1).print();

        env.execute("DataStream API进行wordCount");
    }
}