JavaRDD<Integer> rdd = sc.parallelize(Arrays.asList(1, 2, 3, 3)); Map<Integer, Long> integerLongMap = rdd.countByValue(); 1. 2. reduce rdd.reduce(func) 并行整合RDD中所有数据, 类似于是scala中集合的reduce scala scala> val rdd = sc.parallelize(List(1,2,3,3)) scala> rdd.reduce(...