Spark (JAVA) -具有多个聚合的dataframe groupBy？

import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.SparkSession;
import static org.apache.spark.sql.functions.*;

public class SparkGroupByExample {
    public static void main(String[] args) {
        SparkSession spark = SparkSession.builder()
                .appName("SparkGroupByExample")
                .master("local")
                .getOrCreate();

        // 读取数据文件创建DataFrame
        Dataset<Row> df = spark.read().csv("data.csv");

        // 对age列进行分组，并计算每个分组的平均值和总和
        Dataset<Row> result = df.groupBy("age")
                .agg(avg("salary"), sum("salary"))
                .select("age", "avg(salary)", "sum(salary)");

        result.show();
    }
}