[SPARK-15031][EXAMPLE] Use SparkSession in examples

## What changes were proposed in this pull request?
Use `SparkSession` according to [SPARK-15031](https://issues.apache.org/jira/browse/SPARK-15031)

`MLLLIB` is not recommended to use now, so examples in `MLLIB` are ignored in this PR.
`StreamingContext` can not be directly obtained from `SparkSession`, so example in `Streaming` are ignored too.

cc andrewor14

## How was this patch tested?
manual tests with spark-submit

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #13164 from zhengruifeng/use_sparksession_ii.

1 files changed, 9 insertions, 4 deletions

diff --git a/examples/src/main/python/sort.py b/examples/src/main/python/sort.py
index b6c2916254..81898cf6d5 100755
--- a/examples/src/main/python/sort.py
+++ b/examples/src/main/python/sort.py
@@ -19,15 +19,20 @@ from __future__ import print_function
 
 import sys
 
-from pyspark import SparkContext
+from pyspark.sql import SparkSession
 
 
 if __name__ == "__main__":
     if len(sys.argv) != 2:
         print("Usage: sort <file>", file=sys.stderr)
         exit(-1)
-    sc = SparkContext(appName="PythonSort")
-    lines = sc.textFile(sys.argv[1], 1)
+
+    spark = SparkSession\
+        .builder\
+        .appName("PythonSort")\
+        .getOrCreate()
+
+    lines = spark.read.text(sys.argv[1]).rdd.map(lambda r: r[0])
     sortedCount = lines.flatMap(lambda x: x.split(' ')) \
         .map(lambda x: (int(x), 1)) \
         .sortByKey()
@@ -37,4 +42,4 @@ if __name__ == "__main__":
     for (num, unitcount) in output:
         print(num)
 
-    sc.stop()
+    spark.stop()