假定Session时间设为5秒，那么只要5秒内保持数据流入，那么就认为数据Session没有中断，否则就划分一个Session。

1 1 1 1           1 1 1 1         1 1 1 1           1 1 1 1           1 1 1 1             1 1

两个数据之间的距离不超过5秒，就在一个Session中。

public class SessionWindowAll {

    private static final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
    private static final DataStreamSource<String> stream = env.socketTextStream("192.168.8.111", 8888);

    public static void main(String[] args) throws Exception {
        SingleOutputStreamOperator<Integer> mapped = stream.map((MapFunction<String, Integer>) Integer::valueOf).returns(Types.INT);
        AllWindowedStream<Integer, TimeWindow> processingTimeSessionWindows = mapped.windowAll(ProcessingTimeSessionWindows.withGap(Time.seconds(5)));
        SingleOutputStreamOperator<Integer> summed = processingTimeSessionWindows.sum(0);
        summed.print();
        env.execute("SessionWindowAll");
    }
}

换句话说，输入一个数据超过5秒，就会计算结果。