写了一个代码，直接流（Kafka）字计数时，文件是给定的（在生产者）
代码：

from pyspark import SparkConf, SparkContext

from operator import add
import sys
from pyspark.streaming import StreamingContext
from pyspark.streaming.kafka import KafkaUtils

## Constants

APP_NAME = "PythonStreamingDirectKafkaWordCount"

## OTHER FUNCTIONS/CLASSES

def main():
    sc = SparkContext(appName="PythonStreamingDirectKafkaWordCount")
    ssc = StreamingContext(sc, 2)

    brokers, topic = sys.argv[1:]
    kvs = KafkaUtils.createDirectStream(ssc, [topic], {"metadata.broker.list": brokers})
    lines = kvs.map(lambda x: x[1])
    counts = lines.flatMap(lambda line: line.split(" ")) \
        .map(lambda word: (word, 1)) \
        .reduceByKey(lambda a, b: a+b)
    counts.pprint()

    ssc.start()
    ssc.awaitTermination()
if __name__ == "__main__":

   main()

需要使用dstream将输入json文件转换为spark dataframe。