在使用selenium的过程中我们经常遇到对网页操作的报错，常常程序会停留在这一步，没有办法继续下去，这时候我们就需要对程序做一个异常处理。

添加异常处理

def get_url(driver,url,num_retries = 5):
    try:
        driver.get(url)
        # 切换成frame
        driver.switch_to_frame("g_iframe")
        # 休眠3秒,等待加载完成!
        time.sleep(3)
        html = driver.page_source
        driver.close()
        return html
    except Exception as e:
        if num_retries > 0:
            time.sleep(5)
            print(url)
            print('Requests fail, retry!')
            return get_url(driver = driver,url = url,num_retries = num_retries-1)
        else:
            print("Error:%s"%e)
            return

结果还是出现错误：

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/urllib3/connectionpool.py", line 601, in urlopen
    chunked=chunked)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/connectionpool.py", line 387, in _make_request
    six.raise_from(e, None)
  File "<string>", line 2, in raise_from
  File "/usr/local/lib/python3.6/dist-packages/urllib3/connectionpool.py", line 383, in _make_request
    httplib_response = conn.getresponse()
  File "/usr/lib/python3.6/http/client.py", line 1331, in getresponse
    response.begin()
  File "/usr/lib/python3.6/http/client.py", line 297, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python3.6/http/client.py", line 258, in _read_status
    line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1")
  File "/usr/lib/python3.6/socket.py", line 586, in readinto
    return self._sock.recv_into(b)
ConnectionResetError: [Errno 104] Connection reset by peer

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "get_hot_songs.py", line 73, in <module>
    html = get_html_src(url)
  File "get_hot_songs.py", line 50, in get_html_src
    driver= webdriver.Chrome(chrome_options=chrome_options)
  File "/usr/local/lib/python3.6/dist-packages/selenium/webdriver/chrome/webdriver.py", line 81, in __init__
    desired_capabilities=desired_capabilities)
  File "/usr/local/lib/python3.6/dist-packages/selenium/webdriver/remote/webdriver.py", line 157, in __init__
    self.start_session(capabilities, browser_profile)
  File "/usr/local/lib/python3.6/dist-packages/selenium/webdriver/remote/webdriver.py", line 252, in start_session
    response = self.execute(Command.NEW_SESSION, parameters)
  File "/usr/local/lib/python3.6/dist-packages/selenium/webdriver/remote/webdriver.py", line 319, in execute
    response = self.command_executor.execute(driver_command, params)
  File "/usr/local/lib/python3.6/dist-packages/selenium/webdriver/remote/remote_connection.py", line 374, in execute
    return self._request(command_info[0], url, body=data)
  File "/usr/local/lib/python3.6/dist-packages/selenium/webdriver/remote/remote_connection.py", line 397, in _request
    resp = self._conn.request(method, url, body=body, headers=headers)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/request.py", line 70, in request
    **urlopen_kw)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/request.py", line 148, in request_encode_body
    return self.urlopen(method, url, **extra_kw)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/poolmanager.py", line 321, in urlopen
    response = conn.urlopen(method, u.request_uri, **kw)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/connectionpool.py", line 639, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "/usr/local/lib/python3.6/dist-packages/urllib3/util/retry.py", line 357, in increment
    raise six.reraise(type(error), error, _stacktrace)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/packages/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/connectionpool.py", line 601, in urlopen
    chunked=chunked)
  File "/usr/local/lib/python3.6/dist-packages/urllib3/connectionpool.py", line 387, in _make_request
    six.raise_from(e, None)
  File "<string>", line 2, in raise_from
  File "/usr/local/lib/python3.6/dist-packages/urllib3/connectionpool.py", line 383, in _make_request
    httplib_response = conn.getresponse()
  File "/usr/lib/python3.6/http/client.py", line 1331, in getresponse
    response.begin()
  File "/usr/lib/python3.6/http/client.py", line 297, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python3.6/http/client.py", line 258, in _read_status
    line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1")
  File "/usr/lib/python3.6/socket.py", line 586, in readinto
    return self._sock.recv_into(b)
urllib3.exceptions.ProtocolError: ('Connection aborted.', ConnectionResetError(104, 'Connection reset by peer'))

而且输出中没有看到Requests fail, retry!，说明程序并没有进入到except。下面我对代码进行了修改，将初始化实例放到这个请求函数里面。

def get_url(chrome_options,url,num_retries = 5):
    try:
        # 初始化实例
        driver= webdriver.Chrome(chrome_options=chrome_options)
        driver.get(url)
        # 切换成frame
        driver.switch_to_frame("g_iframe")
        # 休眠3秒,等待加载完成!
        time.sleep(3)
        html = driver.page_source
        driver.close()
        return html
    except Exception as e:
        if num_retries > 0:
            time.sleep(5)
            print(url)
            print('Requests fail, retry!')
            return get_url(chrome_options = chrome_options,url = url,num_retries = num_retries-1)
        else:
            print("Error:%s"%e)
            return

后面程序运行正常，请求失败会按照我的设想进行重复请求！