UDF Java and SQL Examples

package com.xxx.udf;
import org.apache.flink.table.functions.ScalarFunction;
public class UdfClass_UDF extends ScalarFunction {
    public int eval(String s) {
        return s.length();
    }
}

CREATE TEMPORARY FUNCTION udf as 'com.xxx..udf.UdfClass_UDF';
CREATE TABLE udfSource (a VARCHAR) WITH ('connector' = 'datagen','rows-per-second'='1');
CREATE TABLE udfSink (a VARCHAR,b int) WITH ('connector' = 'print');
INSERT INTO
  udfSink
SELECT
  a,
  udf(a)
FROM
  udfSource;