流式计算 优惠卷

import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.api.common.functions.MapFunction;

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

        DataStream<String> text = env.socketTextStream("localhost", 9999);

        DataStream<Double> counts = text
            .map(new MapFunction<String, Double>() {
                public Double map(String value) {
                    return Double.parseDouble(value);
                }
            })
            .timeWindowAll(Time.seconds(1))
            .reduce((value1, value2) -> (value1 + value2) / 2);

        counts.print();

        env.execute("Streaming Average Calculation");
    }
}