如何将Flink中的时间窗口保存为文本文件？

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.assigners.TumblingProcessingTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.util.Collector;

public class SaveWindowToFileExample {

    public static void main(String[] args) throws Exception {
        // 创建执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        // 创建数据流
        DataStream<String> stream = env.socketTextStream("localhost", 9999);

        // 将数据流按空格拆分并计数
        DataStream<Tuple2<String, Integer>> counts = stream
                .flatMap(new Tokenizer())
                .keyBy(0)
                .window(TumblingProcessingTimeWindows.of(Time.seconds(5)))
                .sum(1);

        // 将时间窗口保存为文本文件
        counts.writeAsText("/path/to/output");

        // 执行任务
        env.execute("Save Window to File Example");
    }

    public static final class Tokenizer implements FlatMapFunction<String, Tuple2<String, Integer>> {
        @Override
        public void flatMap(String value, Collector<Tuple2<String, Integer>> out) {
            String[] words = value.toLowerCase().split("\\W+");
            for (String word : words) {
                if (word.length() > 0) {
                    out.collect(new Tuple2<>(word, 1));
                }
            }
        }
    }
}