[Spark][python]以DataFrame方式打开Json文件的例子：
[training@localhost ~]$ cat people.json
{"name":"Alice","pcode":"94304"}
{"name":"Brayden","age":30,"pcode":"94304"}
{"name":"Carla","age":19,"pcoe":"10036"}
{"name":"Diana","age":46}
{"name":"Etienne","pcode":"94104"}
[training@localhost ~]$
[training@localhost ~]$ hdfs dfs -put people.json
[training@localhost ~]$ hdfs dfs -cat people.json
{"name":"Alice","pcode":"94304"}
{"name":"Brayden","age":30,"pcode":"94304"}
{"name":"Carla","age":19,"pcoe":"10036"}
{"name":"Diana","age":46}
{"name":"Etienne","pcode":"94104"}
In [1]: sqlContext = HiveContext(sc)
In [2]: peopleDF = sqlContext.read.json("people.json")
17/10/01 05:20:22 INFO hive.HiveContext: Initializing execution hive, version 1.1.0
17/10/01 05:20:22 INFO client.ClientWrapper: Inspected Hadoop version: 2.6.0-cdh5.7.0
17/10/01 05:20:22 INFO client.ClientWrapper: Loaded org.apache.hadoop.hive.shims.Hadoop23Shims for Hadoop version 2.6.0-cdh5.7.0
17/10/01 05:20:23 INFO hive.metastore: Trying to connect to metastore with URI thrift://localhost.localdomain:9083
17/10/01 05:20:23 INFO hive.metastore: Opened a connection to metastore, current connections: 1
17/10/01 05:20:23 INFO hive.metastore: Connected to metastore.
17/10/01 05:20:23 INFO session.SessionState: Created HDFS directory: file:/tmp/spark-839b35f5-91a1-436c-aae5-922ebacb27f1/scratch/training
17/10/01 05:20:23 INFO session.SessionState: Created local directory: /tmp/b3e52bfc-fe3a-4abe-ac7b-da071104b2f9_resources
17/10/01 05:20:23 INFO session.SessionState: Created HDFS directory: file:/tmp/spark-839b35f5-91a1-436c-aae5-922ebacb27f1/scratch/training/b3e52bfc-fe3a-4abe-ac7b-da071104b2f9
17/10/01 05:20:23 INFO session.SessionState: Created local directory: /tmp/training/b3e52bfc-fe3a-4abe-ac7b-da071104b2f9
17/10/01 05:20:23 INFO session.SessionState: Created HDFS directory: file:/tmp/spark-839b35f5-91a1-436c-aae5-922ebacb27f1/scratch/training/b3e52bfc-fe3a-4abe-ac7b-da071104b2f9/_tmp_space.db
17/10/01 05:20:23 INFO session.SessionState: No Tez session required at this point. hive.execution.engine=mr.
17/10/01 05:20:23 INFO json.JSONRelation: Listing hdfs://localhost:8020/user/training/people.json on driver
17/10/01 05:20:25 INFO storage.MemoryStore: Block broadcast_0 stored as values in memory (estimated size 251.1 KB, free 251.1 KB)
17/10/01 05:20:25 INFO storage.MemoryStore: Block broadcast_0_piece0 stored as bytes in memory (estimated size 21.6 KB, free 272.7 KB)
17/10/01 05:20:25 INFO storage.BlockManagerInfo: Added broadcast_0_piece0 in memory on localhost:42171 (size: 21.6 KB, free: 208.8 MB)
17/10/01 05:20:25 INFO spark.SparkContext: Created broadcast 0 from json at NativeMethodAccessorImpl.java:-2
17/10/01 05:20:26 INFO mapred.FileInputFormat: Total input paths to process : 1
17/10/01 05:20:26 INFO spark.SparkContext: Starting job: json at NativeMethodAccessorImpl.java:-2
17/10/01 05:20:26 INFO scheduler.DAGScheduler: Got job 0 (json at NativeMethodAccessorImpl.java:-2) with 1 output partitions
17/10/01 05:20:26 INFO scheduler.DAGScheduler: Final stage: ResultStage 0 (json at NativeMethodAccessorImpl.java:-2)
17/10/01 05:20:26 INFO scheduler.DAGScheduler: Parents of final stage: List()
17/10/01 05:20:26 INFO scheduler.DAGScheduler: Missing parents: List()
17/10/01 05:20:26 INFO scheduler.DAGScheduler: Submitting ResultStage 0 (MapPartitionsRDD[3] at json at NativeMethodAccessorImpl.java:-2), which has no missing parents
17/10/01 05:20:26 INFO storage.MemoryStore: Block broadcast_1 stored as values in memory (estimated size 4.3 KB, free 277.1 KB)
17/10/01 05:20:26 INFO storage.MemoryStore: Block broadcast_1_piece0 stored as bytes in memory (estimated size 2.4 KB, free 279.5 KB)
17/10/01 05:20:26 INFO storage.BlockManagerInfo: Added broadcast_1_piece0 in memory on localhost:42171 (size: 2.4 KB, free: 208.8 MB)
17/10/01 05:20:26 INFO spark.SparkContext: Created broadcast 1 from broadcast at DAGScheduler.scala:1006
17/10/01 05:20:26 INFO scheduler.DAGScheduler: Submitting 1 missing tasks from ResultStage 0 (MapPartitionsRDD[3] at json at NativeMethodAccessorImpl.java:-2)
17/10/01 05:20:26 INFO scheduler.TaskSchedulerImpl: Adding task set 0.0 with 1 tasks
17/10/01 05:20:26 INFO scheduler.TaskSetManager: Starting task 0.0 in stage 0.0 (TID 0, localhost, partition 0,PROCESS_LOCAL, 2149 bytes)
17/10/01 05:20:26 INFO executor.Executor: Running task 0.0 in stage 0.0 (TID 0)
17/10/01 05:20:26 INFO rdd.HadoopRDD: Input split: hdfs://localhost:8020/user/training/people.json:0+179
17/10/01 05:20:27 INFO Configuration.deprecation: mapred.tip.id is deprecated. Instead, use mapreduce.task.id
17/10/01 05:20:27 INFO Configuration.deprecation: mapred.task.id is deprecated. Instead, use mapreduce.task.attempt.id
17/10/01 05:20:27 INFO Configuration.deprecation: mapred.task.is.map is deprecated. Instead, use mapreduce.task.ismap
17/10/01 05:20:27 INFO Configuration.deprecation: mapred.task.partition is deprecated. Instead, use mapreduce.task.partition
17/10/01 05:20:27 INFO Configuration.deprecation: mapred.job.id is deprecated. Instead, use mapreduce.job.id
17/10/01 05:20:27 INFO executor.Executor: Finished task 0.0 in stage 0.0 (TID 0). 2354 bytes result sent to driver
17/10/01 05:20:27 INFO scheduler.DAGScheduler: ResultStage 0 (json at NativeMethodAccessorImpl.java:-2) finished in 0.715 s
17/10/01 05:20:27 INFO scheduler.TaskSetManager: Finished task 0.0 in stage 0.0 (TID 0) in 667 ms on localhost (1/1)
17/10/01 05:20:27 INFO scheduler.TaskSchedulerImpl: Removed TaskSet 0.0, whose tasks have all completed, from pool
17/10/01 05:20:27 INFO scheduler.DAGScheduler: Job 0 finished: json at NativeMethodAccessorImpl.java:-2, took 1.084685 s
17/10/01 05:20:27 INFO hive.HiveContext: default warehouse location is /user/hive/warehouse
17/10/01 05:20:28 INFO hive.HiveContext: Initializing metastore client version 1.1.0 using Spark classes.
17/10/01 05:20:28 INFO client.ClientWrapper: Inspected Hadoop version: 2.6.0-cdh5.7.0
17/10/01 05:20:28 INFO client.ClientWrapper: Loaded org.apache.hadoop.hive.shims.Hadoop23Shims for Hadoop version 2.6.0-cdh5.7.0
17/10/01 05:20:28 INFO storage.BlockManagerInfo: Removed broadcast_1_piece0 on localhost:42171 in memory (size: 2.4 KB, free: 208.8 MB)
17/10/01 05:20:28 INFO spark.ContextCleaner: Cleaned accumulator 2
17/10/01 05:20:30 INFO hive.metastore: Trying to connect to metastore with URI thrift://localhost.localdomain:9083
17/10/01 05:20:30 INFO hive.metastore: Opened a connection to metastore, current connections: 1
17/10/01 05:20:30 INFO hive.metastore: Connected to metastore.
17/10/01 05:20:30 INFO session.SessionState: Created HDFS directory: /tmp/hive/training
17/10/01 05:20:30 INFO session.SessionState: Created local directory: /tmp/8c1eba54-7260-4314-abbf-7b7de85bdf0a_resources
17/10/01 05:20:30 INFO session.SessionState: Created HDFS directory: /tmp/hive/training/8c1eba54-7260-4314-abbf-7b7de85bdf0a
17/10/01 05:20:30 INFO session.SessionState: Created local directory: /tmp/training/8c1eba54-7260-4314-abbf-7b7de85bdf0a
17/10/01 05:20:30 INFO session.SessionState: Created HDFS directory: /tmp/hive/training/8c1eba54-7260-4314-abbf-7b7de85bdf0a/_tmp_space.db
17/10/01 05:20:30 INFO session.SessionState: No Tez session required at this point. hive.execution.engine=mr.
In [3]: type(peopleDF)
Out[3]: pyspark.sql.dataframe.DataFrame
In [4]: