视频开头说用with可以释放资源，但是用try_except_finally时有异常可以继续完成后面的代码，用with时有异常并没有正常结束程序，怎么看出它释放资源了？

老师，为什么我的电脑可以装mysql5.7,却在装mysql8.0时一直卡在了starting server这一步？

这几集的笔记和资料能不能补发一下下下下？老师

老师 服务器接收浏览器信息的时候，无论是用转换流指定gbk ,utf—8字符集，还是用字节数组，打印出来全都是乱码，这样的情况应该怎么办呢？

老师，我爬取豆瓣电影代码如下：

from urllib.request import Request
from urllib.request import urlopen
from random import choice
from time import sleep


def get_html(url):
    user_agnet_list = [
        # 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko)\
        #  Chrome/80.0.3987.132 Safari/537.36'
        # 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; 360SE)123456',
        # 'Opera/9.80 (Windows NT 6.1; U; en) Presto/2.8.131 Version/11.11',
        # 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; TencentTraveler 4.0)',
        # 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; The World)',
        # 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SE 2.X MetaSr 1.0; SE 2.X MetaSr 1.0; \
        # .NET CLR 2.0.50727; SE 2.X MetaSr 1.0)',
        # 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)',
        # 'Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_8; en-us) AppleWebKit/534.50(KHTML, like Gecko)\
        #  Version/5.1 Safari/534.50'
        'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36'
    ]
    choice_agent = choice(user_agnet_list)
    headers = {
        'User-Agent': choice_agent
    }
    request = Request(url, headers=headers)
    response = urlopen(request)
    return response.read().decode()


def save_html(html, filename):
    with open(filename, 'a', encoding='utf-8') as f:
        f.writelines(html)


def main():
    i = 0
    base_url = 'https://movie.douban.com/j/chart/top_list?type=11&interval_id=100%3A90&action=&start={}&limit=20'
    while True:
        url = base_url.format(i * 20)
        html = get_html(url)
        if html == '[]':  # 返回值为[]时表示遍历完成，退出循环
            break
        else:
            print(html)
            save_html(html, 'a.html')
            i += 1
            sleep(3)
    # html=get_html(base_url)
    # print(html)


if __name__ == '__main__':
    main()

刚开始运行还能运行，后面运行提示：

是不是被封ip了？如何解决？

老师，爬取豆瓣电影时，

如果想提高访问效率，limit=20可以改成200，那么前面的start规则是不是也就变了，是不是每次不在增加20了？

https://www.sxt.cn/Java_jQuery_in_action/History_Direction.html

老师这个链接的文档是还没更新呢吗  感觉有好多东西和视频不太符合  后面的也不全 

老师，这三集视频的资料有问题。资料下载下来是这图片里的资料；根本没有virtualenvwrapper的文档资料

老师，我为什么不在浏览器中显示输入url后直接下载了

2020-03-14 16:33:59 [scrapy.utils.log] INFO: Scrapy 2.0.0 started (bot: rockstone)
2020-03-14 16:33:59 [scrapy.utils.log] INFO: Versions: lxml 4.5.0.0, libxml2 2.9.5, cssselect 1.1.0, parsel 1.5.2, w3lib 1.21.0, Twisted 19.10.0, Python 3.7.6 (tags/v3.7.6:43364
a7ae0, Dec 19 2019, 00:42:30) [MSC v.1916 64 bit (AMD64)], pyOpenSSL 19.1.0 (OpenSSL 1.1.1d  10 Sep 2019), cryptography 2.8, Platform Windows-10-10.0.18362-SP0
2020-03-14 16:33:59 [scrapy.utils.log] DEBUG: Using reactor: twisted.internet.selectreactor.SelectReactor
2020-03-14 16:33:59 [scrapy.crawler] INFO: Overridden settings:
{'BOT_NAME': 'rockstone',
 'NEWSPIDER_MODULE': 'rockstone.spiders',
 'ROBOTSTXT_OBEY': True,
 'SPIDER_MODULES': ['rockstone.spiders']}
2020-03-14 16:33:59 [scrapy.extensions.telnet] INFO: Telnet Password: 12ce7d6c067a2499
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.logstats.LogStats']
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware',
 'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 'scrapy.downloadermiddlewares.retry.RetryMiddleware',
 'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
 'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
 'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
 'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
 'scrapy.downloadermiddlewares.stats.DownloaderStats']
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
 'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
 'scrapy.spidermiddlewares.referer.RefererMiddleware',
 'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
 'scrapy.spidermiddlewares.depth.DepthMiddleware']
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2020-03-14 16:33:59 [scrapy.core.engine] INFO: Spider opened
2020-03-14 16:33:59 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2020-03-14 16:33:59 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023
2020-03-14 16:33:59 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://www.baidu.com/robots.txt> (referer: None)
2020-03-14 16:33:59 [scrapy.downloadermiddlewares.robotstxt] DEBUG: Forbidden by robots.txt: <GET http://www.baidu.com/>
2020-03-14 16:33:59 [scrapy.core.engine] INFO: Closing spider (finished)
2020-03-14 16:33:59 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/exception_count': 1,
 'downloader/exception_type_count/scrapy.exceptions.IgnoreRequest': 1,
 'downloader/request_bytes': 223,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 676,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'elapsed_time_seconds': 0.350322,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2020, 3, 14, 8, 33, 59, 677262),
 'log_count/DEBUG': 2,
 'log_count/INFO': 10,
 'response_received_count': 1,
 'robotstxt/forbidden': 1,
 'robotstxt/request_count': 1,
 'robotstxt/response_count': 1,
 'robotstxt/response_status_count/200': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2020, 3, 14, 8, 33, 59, 326940)}
2020-03-14 16:33:59 [scrapy.core.engine] INFO: Spider closed (finished)

老师 我这个按照百度那个测试     没有返回的html信息

2020-03-14 16:33:59 [scrapy.utils.log] INFO: Scrapy 2.0.0 started (bot: rockstone)
2020-03-14 16:33:59 [scrapy.utils.log] INFO: Versions: lxml 4.5.0.0, libxml2 2.9.5, cssselect 1.1.0, parsel 1.5.2, w3lib 1.21.0, Twisted 19.10.0, Python 3.7.6 (tags/v3.7.6:43364
a7ae0, Dec 19 2019, 00:42:30) [MSC v.1916 64 bit (AMD64)], pyOpenSSL 19.1.0 (OpenSSL 1.1.1d  10 Sep 2019), cryptography 2.8, Platform Windows-10-10.0.18362-SP0
2020-03-14 16:33:59 [scrapy.utils.log] DEBUG: Using reactor: twisted.internet.selectreactor.SelectReactor
2020-03-14 16:33:59 [scrapy.crawler] INFO: Overridden settings:
{'BOT_NAME': 'rockstone',
 'NEWSPIDER_MODULE': 'rockstone.spiders',
 'ROBOTSTXT_OBEY': True,
 'SPIDER_MODULES': ['rockstone.spiders']}
2020-03-14 16:33:59 [scrapy.extensions.telnet] INFO: Telnet Password: 12ce7d6c067a2499
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.logstats.LogStats']
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware',
 'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 'scrapy.downloadermiddlewares.retry.RetryMiddleware',
 'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
 'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
 'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
 'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
 'scrapy.downloadermiddlewares.stats.DownloaderStats']
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
 'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
 'scrapy.spidermiddlewares.referer.RefererMiddleware',
 'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
 'scrapy.spidermiddlewares.depth.DepthMiddleware']
2020-03-14 16:33:59 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2020-03-14 16:33:59 [scrapy.core.engine] INFO: Spider opened
2020-03-14 16:33:59 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2020-03-14 16:33:59 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023
2020-03-14 16:33:59 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://www.baidu.com/robots.txt> (referer: None)
2020-03-14 16:33:59 [scrapy.downloadermiddlewares.robotstxt] DEBUG: Forbidden by robots.txt: <GET http://www.baidu.com/>
2020-03-14 16:33:59 [scrapy.core.engine] INFO: Closing spider (finished)
2020-03-14 16:33:59 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/exception_count': 1,
 'downloader/exception_type_count/scrapy.exceptions.IgnoreRequest': 1,
 'downloader/request_bytes': 223,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 676,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'elapsed_time_seconds': 0.350322,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2020, 3, 14, 8, 33, 59, 677262),
 'log_count/DEBUG': 2,
 'log_count/INFO': 10,
 'response_received_count': 1,
 'robotstxt/forbidden': 1,
 'robotstxt/request_count': 1,
 'robotstxt/response_count': 1,
 'robotstxt/response_status_count/200': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2020, 3, 14, 8, 33, 59, 326940)}
2020-03-14 16:33:59 [scrapy.core.engine] INFO: Spider closed (finished)

老师 我这个按照百度那个测试     没有返回的html信息

老师，这个地方为什么还要返回父类的初始化方法呢？

一个localhost变成了eureka1，但是另外一个没变

老师，为什么不加上述继承父类的new方法，不会报错，反而输出途中结果

另外，

return super(AA,cls).__new__(cls) 中AA是干嘛用的，之前讲义里讲的super（self）表示父类定义，没见过还往里加其他参数的

老师，请问下这个项目是后端的项目么。。。。