在JavaRDD中使用Text数据类型并在FlatMap中返回空

import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.FlatMapFunction;
import org.apache.spark.api.java.function.Function;
import org.apache.spark.api.java.function.VoidFunction;
import org.apache.spark.sql.SparkSession;
import scala.Tuple2;
import java.util.Arrays;
import java.util.Iterator;

SparkConf conf = new SparkConf().setAppName("JavaRDDExample").setMaster("local");

JavaSparkContext sc = new JavaSparkContext(conf);

JavaRDD<Text> textRDD = sc.textFile("path/to/textfile.txt").map(new Function<String, Text>() {
    @Override
    public Text call(String line) throws Exception {
        return new Text(line);
    }
});

JavaRDD<String> emptyRDD = textRDD.flatMap(new FlatMapFunction<Text, String>() {
    @Override
    public Iterator<String> call(Text text) throws Exception {
        return Arrays.asList().iterator();
    }
});