Pyspark初始化SparkContext时，报jvm不存在错误

错误如下

----> 1 sc = SparkContext(conf=conf)

/usr/local/lib/python3.6/site-packages/pyspark/context.py in __init__(self, master, appName, sparkHome, pyFiles, environment, batchSize, serializer, conf, gateway, jsc, profiler_cls)
    145         try:
    146             self._do_init(master, appName, sparkHome, pyFiles, environment, batchSize, serializer,
--> 147                           conf, jsc, profiler_cls)
    148         except:
    149             # If an error occurs, clean up in order to allow future SparkContext creation:

/usr/local/lib/python3.6/site-packages/pyspark/context.py in _do_init(self, master, appName, sparkHome, pyFiles, environment, batchSize, serializer, conf, jsc, profiler_cls)
    222         # data via a socket.
    223         # scala's mangled names w/ $ in them require special treatment.
--> 224         self._encryption_enabled = self._jvm.PythonUtils.isEncryptionEnabled(self._jsc)
    225         os.environ["SPARK_AUTH_SOCKET_TIMEOUT"] = \
    226             str(self._jvm.PythonUtils.getPythonAuthSocketTimeout(self._jsc))

/usr/local/lib/python3.6/site-packages/py4j/java_gateway.py in __getattr__(self, name)
   1529         else:
   1530             raise Py4JError(
-> 1531                 "{0}.{1} does not exist in the JVM".format(self._fqn, name))
   1532 
   1533     def _get_args(self, args):

Py4JError: org.apache.spark.api.python.PythonUtils.isEncryptionEnabled does not exist in the JVM

我的解决方法：
添加下面内容到~/.bashrc

export SPARK_HOME=/usr/local/spark
export PYTHONPATH=$SPARK_HOME/python:$SPARK_HOME/python/lib/py4j-0.10.7-src.zip:$PYTHONPATH
export PATH=$SPARK_HOME/bin:$SPARK_HOME/python:$PATH

参考:
https://www.py4u.net/discuss/164056