当我用交替最小二乘法进行矩阵分解时，我在spark中遇到了java服务器的错误，我不知道为什么会发生这种情况，下面是错误消息。

Exception happened during processing of request from ('127.0.0.1', 61711)
Traceback (most recent call last):
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/socketserver.py", line 316, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/socketserver.py", line 347, in process_request
    self.finish_request(request, client_address)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/socketserver.py", line 360, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/socketserver.py", line 720, in __init__
    self.handle()
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/accumulators.py", line 262, in handle
    poll(accum_updates)
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/accumulators.py", line 235, in poll
    if func():
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/accumulators.py", line 239, in accum_updates
    num_updates = read_int(self.rfile)
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/serializers.py", line 564, in read_int
    raise EOFError
EOFError
----------------------------------------
ERROR:py4j.java_gateway:An error occurred while trying to connect to the Java server (127.0.0.1:61698)
Traceback (most recent call last):
  File "/Users/zhengyangzhang/Library/Python/3.8/lib/python/site-packages/IPython/core/interactiveshell.py", line 3417, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-3-deb1baad55f8>", line 15, in <module>
    MSE = ratesAndPreds.map(lambda r: (r[1][0] - r[1][1])**2).mean()
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/rdd.py", line 1386, in mean
    return self.stats().mean()
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/rdd.py", line 1245, in stats
    return self.mapPartitions(lambda i: [StatCounter(i)]).reduce(redFunc)
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/rdd.py", line 997, in reduce
    vals = self.mapPartitions(func).collect()
  File "/usr/local/opt/apache-spark/libexec/python/pyspark/rdd.py", line 949, in collect
    sock_info = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd())
  File "/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py", line 1304, in __call__
    return_value = get_return_value(
  File "/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.9-src.zip/py4j/protocol.py", line 326, in get_return_value
    raise Py4JJavaError(
py4j.protocol.Py4JJavaError: <unprintable Py4JJavaError object>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/zhengyangzhang/Library/Python/3.8/lib/python/site-packages/IPython/core/interactiveshell.py", line 2044, in showtraceback
    stb = value._render_traceback_()
AttributeError: 'Py4JJavaError' object has no attribute '_render_traceback_'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py", line 1207, in send_command
    raise Py4JNetworkError("Answer from Java side is empty")
py4j.protocol.Py4JNetworkError: Answer from Java side is empty

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py", line 1033, in send_command
    response = connection.send_command(command)
  File "/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py", line 1211, in send_command
    raise Py4JNetworkError(
py4j.protocol.Py4JNetworkError: Error while receiving

下面的信息在我的jupyter笔记本上重复了几百次。

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py", line 977, in _get_connection
    connection = self.deque.pop()
IndexError: pop from an empty deque

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py", line 1115, in start
    self.socket.connect((self.address, self.port))
ConnectionRefusedError: [Errno 61] Connection refused

我张贴这个问题，因为我只是不明白为什么会发生这种情况，如果有人能向我解释为什么会发生这种情况，并为我提供一个可能的解决方案，我将非常感谢。
下面是我的导入包和设置列表：

import findspark
findspark.init()
from pyspark import SparkContext
from pyspark.mllib.recommendation import ALS, MatrixFactorizationModel, Rating

我在网上看到findspark包可能有助于解决这个问题，所以我编写了apachespark和pip这个包，但是仍然有问题。