Transformer.java

private void transformToJson() {
      SparkSession spark = SparkSession.builder()
              .config("spark.master", "local")
              .appName("Java Spark SQL basic example").getOrCreate();
      String query = "SELECT id, title, description, author, year, edition, publisher FROM books order by id";
      Dataset<Row> jdbcDF = spark.read().format("jdbc")
              .option("url", propertyLoader.getJdbcConnectionString())
              .option("user", propertyLoader.getDatabaseUserName())
              .option("password", propertyLoader.getDatabasePassword())
              .option("numPartitions", "10")
              .option("partitionColumn", "id")
              .option("lowerBound", "0")
              .option("upperBound", Long.MAX_VALUE)
              .option("driver", "com.mysql.jdbc.Driver")
              .option("dbtable", String.format("(%s) AS tmp", query))
              .load();
      jdbcDF.write().format("json").mode("append").save("books_json");
      spark.close();
  }