UDTF Java and SQL Examples

package com.xxx.udf;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.table.functions.TableFunction;
public class UdfClass_UDTF extends TableFunction<Tuple2<String, Integer>> {
    public void eval(String str) {
        Tuple2<String, Integer> tuple2 = Tuple2.of(str, str.length());
        collect(tuple2);
    }
}

CREATE TEMPORARY FUNCTION udtf as 'com.xxx.udf.UdfClass_UDTF';
CREATE TABLE udfSource (a VARCHAR) WITH ('connector' = 'datagen','rows-per-second'='1');
CREATE TABLE udfSink (b VARCHAR,c int) WITH ('connector' = 'print');
INSERT INTO
  udfSink
SELECT
  str,
  strLength
FROM
  udfSource,lateral table(udtf(udfSource.a)) as T(str,strLength);