[SPARK-9812] [STREAMING] Fix Python 3 compatibility issue in PySpark Streaming and some docs

This PR includes the following fixes:
1. Use `range` instead of `xrange` in `queue_stream.py` to support Python 3.
2. Fix the issue that `utf8_decoder` will return `bytes` rather than `str` when receiving an empty `bytes` in Python 3.
3. Fix the commands in docs so that the user can copy them directly to the command line. The previous commands was broken in the middle of a path, so when copying to the command line, the path would be split to two parts by the extra spaces, which forces the user to fix it manually.

Author: zsxwing <zsxwing@gmail.com>

Closes #8315 from zsxwing/SPARK-9812.

1 files changed, 3 insertions, 3 deletions

diff --git a/examples/src/main/python/streaming/direct_kafka_wordcount.py b/examples/src/main/python/streaming/direct_kafka_wordcount.py
index 6ef188a220..ea20678b9a 100644
--- a/examples/src/main/python/streaming/direct_kafka_wordcount.py
+++ b/examples/src/main/python/streaming/direct_kafka_wordcount.py
@@ -23,8 +23,8 @@
  http://kafka.apache.org/documentation.html#quickstart
 
  and then run the example
-    `$ bin/spark-submit --jars external/kafka-assembly/target/scala-*/\
-      spark-streaming-kafka-assembly-*.jar \
+    `$ bin/spark-submit --jars \
+      external/kafka-assembly/target/scala-*/spark-streaming-kafka-assembly-*.jar \
       examples/src/main/python/streaming/direct_kafka_wordcount.py \
       localhost:9092 test`
 """
@@ -37,7 +37,7 @@ from pyspark.streaming.kafka import KafkaUtils
 
 if __name__ == "__main__":
     if len(sys.argv) != 3:
-        print >> sys.stderr, "Usage: direct_kafka_wordcount.py <broker_list> <topic>"
+        print("Usage: direct_kafka_wordcount.py <broker_list> <topic>", file=sys.stderr)
         exit(-1)
 
     sc = SparkContext(appName="PythonStreamingDirectKafkaWordCount")