【pip安装python报错】socket.timeout:The read operation timed out问题的解决方法

(ocr) [root@localhost.localdomain /usr/local/OCR/chineseocr_lite-onnx_v1.0.1]#pip3 install -r requirements.txt -i https://mirrors.aliyun.com/pypi/simple/
Looking in indexes: https://mirrors.aliyun.com/pypi/simple/
Collecting tornado==5.1.1
  Downloading https://mirrors.aliyun.com/pypi/packages/e6/78/6e7b5af12c12bdf38ca9bfe863fcaf53dc10430a312d0324e76c1e5ca426/tornado-5.1.1.tar.gz (516 kB)
     |████████████████████████████████| 516 kB 13 kB/s 
Collecting numpy==1.19.1
  Downloading https://mirrors.aliyun.com/pypi/packages/b1/9a/7d474ba0860a41f771c9523d8c4ea56b084840b5ca4092d96bdee8a3b684/numpy-1.19.1-cp36-cp36m-manylinux2010_x86_64.whl (14.5 MB)
     |██████████████████████▎         | 10.1 MB 7.8 kB/s eta 0:09:22ERROR: Exception:
Traceback (most recent call last):
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_vendor/urllib3/response.py", line 437, in _error_catcher
    yield
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_vendor/urllib3/response.py", line 519, in read
    data = self._fp.read(amt) if not fp_closed else b""
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_vendor/cachecontrol/filewrapper.py", line 62, in read
    data = self.__fp.read(amt)
  File "/root/miniconda3/envs/ocr/lib/python3.6/http/client.py", line 449, in read
    n = self.readinto(b)
  File "/root/miniconda3/envs/ocr/lib/python3.6/http/client.py", line 493, in readinto
    n = self.fp.readinto(b)
  File "/root/miniconda3/envs/ocr/lib/python3.6/socket.py", line 586, in readinto
    return self._sock.recv_into(b)
  File "/root/miniconda3/envs/ocr/lib/python3.6/ssl.py", line 1009, in recv_into
    return self.read(nbytes, buffer)
  File "/root/miniconda3/envs/ocr/lib/python3.6/ssl.py", line 871, in read
    return self._sslobj.read(len, buffer)
  File "/root/miniconda3/envs/ocr/lib/python3.6/ssl.py", line 631, in read
    v = self._sslobj.read(len, buffer)
socket.timeout: The read operation timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/cli/base_command.py", line 228, in _main
    status = self.run(options, args)
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/cli/req_command.py", line 182, in wrapper
    return func(self, options, args)
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/commands/install.py", line 324, in run
    reqs, check_supported_wheels=not options.target_dir
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/resolution/legacy/resolver.py", line 183, in resolve
    discovered_reqs.extend(self._resolve_one(requirement_set, req))
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/resolution/legacy/resolver.py", line 388, in _resolve_one
    abstract_dist = self._get_abstract_dist_for(req_to_install)
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/resolution/legacy/resolver.py", line 340, in _get_abstract_dist_for
    abstract_dist = self.preparer.prepare_linked_requirement(req)
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 469, in prepare_linked_requirement
    hashes=self._get_linked_req_hashes(req)
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 259, in unpack_url
    hashes=hashes,
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 130, in get_http_url
    link, downloader, temp_dir.path, hashes
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 282, in _download_http_url
    for chunk in download.chunks:
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/cli/progress_bars.py", line 168, in iter
    for x in it:
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_internal/network/utils.py", line 88, in response_chunks
    decode_content=False,
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_vendor/urllib3/response.py", line 576, in stream
    data = self.read(amt=amt, decode_content=decode_content)
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_vendor/urllib3/response.py", line 541, in read
    raise IncompleteRead(self._fp_bytes_read, self.length_remaining)
  File "/root/miniconda3/envs/ocr/lib/python3.6/contextlib.py", line 99, in __exit__
    self.gen.throw(type, value, traceback)
  File "/root/miniconda3/envs/ocr/lib/python3.6/site-packages/pip/_vendor/urllib3/response.py", line 442, in _error_catcher
    raise ReadTimeoutError(self._pool, None, "Read timed out.")
pip._vendor.urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='mirrors.aliyun.com', port=443): Read timed out.
(ocr) [root@localhost.localdomain /usr/local/OCR/chineseocr_lite-onnx_v1.0.1]#    
(ocr) [root@localhost.localdomain /usr/local/OCR/chineseocr_lite-onnx_v1.0.1]#pip3 list
Package    Version
---------- -------------------
certifi    2020.6.20
pip        20.2.4
setuptools 50.3.1.post20201107
wheel      0.35.1

一般是由于网速不稳定，下载过慢，超出默认时间，所以只要修改一下响应时间就好了。
方法如下:
windows下输入 pip --default-timeout=100 install 包名
linux下输入 pip --default-timeout=100 install -U 包名