hadoop编译源码介绍
hadoop3.x编译源码（centos7平台，支持snappy）
aggregateByKey算子报错 org.apache.spark.SparkException: Task not serializable
scala不建议用return
spark3.0教程：RDD行动算子fold()
spark3.0教程：RDD行动算子aggregate()
spark3.0教程：RDD行动算子foreach()
spark3.0教程：RDD行动算子saveAsSequenceFile
spark3.0教程：RDD行动算子saveAsObjectFile
spark3.0教程：RDD行动算子saveAsTextFile