问如何解决异常:Windows10中Java网关进程在发送端口号前已退出

EN

import pyspark
from pyspark import SparkContext
sc = SparkContext(appName="Pyspark mllib Example")
'cmd' is not recognized as an internal or external command,
operable program or batch file.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\AppData\Local\Programs\Python\Python37\lib\site-packages\pyspark\context.py", line 133, in __init__
    SparkContext._ensure_initialized(self, gateway=gateway, conf=conf)
  File "C:\Users\AppData\Local\Programs\Python\Python37\lib\site-packages\pyspark\context.py", line 316, in _ensure_initialized
    SparkContext._gateway = gateway or launch_gateway(conf)
  File "C:\Users\AppData\Local\Programs\Python\Python37\lib\site-packages\pyspark\java_gateway.py", line 46, in launch_gateway
    return _launch_gateway(conf)
  File "C:\Users\AppData\Local\Programs\Python\Python37\lib\site-packages\pyspark\java_gateway.py", line 108, in _launch_gateway
    raise Exception("Java gateway process exited before sending its port number")
**Exception: Java gateway process exited before sending its port number**

Exception: Java gateway process exited before sending its port number