老师，在

Button(f1,text="百战程序员").place(relx=0.5,rely=0.7,x=100)

中添加x=100，为什么百战程序员无法显示出来了

老师您能把shiro的jar包上传一下吗，现在官网下不了了，上传的资料也损坏了

这个是第八阶段32节课讲到，发错地方啦。

老师：我运行代码就报错，

2020-03-30 15:25:37 [scrapy.utils.log] INFO: Scrapy 2.0.1 started (bot: book)

2020-03-30 15:25:37 [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 20.3.0, Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 23:11:46) [MSC v.1916 64 bit (AMD64)], pyOpenSSL 19.1.0 (OpenSSL 1.1.1d  10 Sep 2019), cryptography 2.8, Platform Windows-10-10.0.17763-SP0

2020-03-30 15:25:37 [scrapy.utils.log] DEBUG: Using reactor: twisted.internet.selectreactor.SelectReactor

2020-03-30 15:25:37 [scrapy.crawler] INFO: Overridden settings:

{'BOT_NAME': 'book',

 'NEWSPIDER_MODULE': 'book.spiders',

 'SPIDER_MODULES': ['book.spiders'],

 'USER_AGENT': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 '

               '(KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36'}

2020-03-30 15:25:37 [scrapy.extensions.telnet] INFO: Telnet Password: 55216b70a4289d90

2020-03-30 15:25:37 [scrapy.middleware] INFO: Enabled extensions:

['scrapy.extensions.corestats.CoreStats',

 'scrapy.extensions.telnet.TelnetConsole',

 'scrapy.extensions.logstats.LogStats']

2020-03-30 15:25:37 [scrapy.middleware] INFO: Enabled downloader middlewares:

['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']

2020-03-30 15:25:37 [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']

2020-03-30 15:25:37 [scrapy.middleware] INFO: Enabled item pipelines:

[]

2020-03-30 15:25:37 [scrapy.core.engine] INFO: Spider opened

2020-03-30 15:25:37 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)

2020-03-30 15:25:37 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023

2020-03-30 15:25:37 [scrapy.core.scraper] ERROR: Error downloading <GET htttp://www.zongheng.com/rank/details.html?rt=1&p=1>

Traceback (most recent call last):

  File "C:\Programs\Python\Python38\lib\site-packages\twisted\internet\defer.py", line 1416, in _inlineCallbacks

    result = result.throwExceptionIntoGenerator(g)

  File "C:\Programs\Python\Python38\lib\site-packages\twisted\python\failure.py", line 512, in throwExceptionIntoGenerator

    return g.throw(self.type, self.value, self.tb)

  File "C:\Programs\Python\Python38\lib\site-packages\scrapy\core\downloader\middleware.py", line 42, in process_request

    defer.returnValue((yield download_func(request=request, spider=spider)))

  File "C:\Programs\Python\Python38\lib\site-packages\scrapy\utils\defer.py", line 55, in mustbe_deferred

    result = f(*args, **kw)

  File "C:\Programs\Python\Python38\lib\site-packages\scrapy\core\downloader\handlers\__init__.py", line 74, in download_request

    raise NotSupported("Unsupported URL scheme '%s': %s" %

scrapy.exceptions.NotSupported: Unsupported URL scheme 'htttp': no handler available for that scheme

2020-03-30 15:25:37 [scrapy.core.engine] INFO: Closing spider (finished)

2020-03-30 15:25:37 [scrapy.statscollectors] INFO: Dumping Scrapy stats:

{'downloader/exception_count': 1,

 'downloader/exception_type_count/scrapy.exceptions.NotSupported': 1,

 'downloader/request_bytes': 323,

 'downloader/request_count': 1,

 'downloader/request_method_count/GET': 1,

 'elapsed_time_seconds': 0.324646,

 'finish_reason': 'finished',

 'finish_time': datetime.datetime(2020, 3, 30, 7, 25, 37, 768198),

 'log_count/ERROR': 1,

 'log_count/INFO': 10,

 'scheduler/dequeued': 1,

 'scheduler/dequeued/memory': 1,

 'scheduler/enqueued': 1,

 'scheduler/enqueued/memory': 1,

 'start_time': datetime.datetime(2020, 3, 30, 7, 25, 37, 443552)}

2020-03-30 15:25:37 [scrapy.core.engine] INFO: Spider closed (finished)

老师这个isset的方法是不是只用在$_GET上

老师，我总是报下面的错误，该怎么解决，我百度了但是没找到什么有效地方法

# coding=utf-8
"""开发记事本软件，使用面向对象的编程方式"""
from tkinter import *
from tkinter.filedialog import *
from tkinter.colorchooser import *


class Application(Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.textPad = None
        self.filename = None
        self.Contextmenu = None
        self.pack()
        self.creatwidget()

    def creatwidget(self):
        # 创建菜单
        menubar = Menu(root)
        menuFile = Menu(menubar)
        menuEdit = Menu(menubar)
        menuHelp = Menu(menubar)

        # 把菜单添加到主菜单中
        menubar.add_cascade(label="文件F", menu=menuFile)
        menubar.add_cascade(label="编辑E", menu=menuEdit)
        menubar.add_cascade(label="帮助H", menu=menuHelp)

        # 在文件菜单下添加选项
        # 都可以通过command参数绑定方法，此处省略
        # accelerator是快捷键参数
        menuFile.add_command(label="新建N", accelerator="ctrl+n")
        menuFile.add_command(label="打开O", accelerator="ctrl+o",
                             command=self.openfile)
        menuFile.add_command(label="保存S", accelerator="ctrl+s",
                             command=self.savefile)
        # 添加一道下滑线
        menuFile.add_separator()
        menuFile.add_command(label="退出", accelerator="ctrl+q",
                             command=self.exit)

        # 添加上下文菜单，即右键快捷菜单
        self.Contextmenu = Menu(self.master)
        self.Contextmenu.add_command(label="选择背景颜色", command=self.choosebgcolor)
        self.master.bind("<Button-3>", self.ms)

        # 把主菜单添加到主窗口
        root.config(menu=menubar)
        self.textPad = Text(self.master, width=300, height=300, bg="gray")
        self.textPad.pack()

        # 绑定快捷键
        root.bind("<Control-o>", self.openfile)
        root.bind("<Control-s>", self.savefile)
        root.bind("<Control-q>", self.exit)
        root.bind("<Control-n>", self.newfile)

    def ms(self, event):
        self.Contextmenu.post(event.x_root, event.y_root)

    def exit(self, event=None):
        self.master.quit()

    def openfile(self, event=None):
        self.textPad.delete(1.0, END)
        with askopenfile(title="打开文本文件", filetypes=[("文本文件", ".txt")]) as file:
            self.filename = file.name
            self.textPad.insert(INSERT, file.read())

    def savefile(self, event=None):
        with open(self.filename, "w") as file:
            c = self.textPad.get(1.0, END)
            file.write(c)

    def newfile(self, event=None):
        self.textPad.delete(1.0, END)
        self.filename = asksaveasfilename(title="新建文件",
                                          initialfile="未命名.txt", filetypes=[(
                "文本文件", ".txt")], defaultextension=".txt")

    def choosebgcolor(self):
        colors = askcolor(color="gray", title="选择背景颜色")
        self.textPad.config(bg=colors[1])


if __name__ == "__main__":
    root = Tk()
    root.geometry('500x500')
    app = Application(root)

    root.mainloop()

这一个是什么连接，能不能详细说明一下他的作用？

怎样查看查询数据是否大于3%呢，能不能详细说一下？

请问关闭流，什么时候需要判断是否为null，什么时候不需要判断直接关闭？

请问老师，在分层结构中，数据表持久层中的方法，与业务层的方法，是否需要一一对应，因为不同的业务其对应的sql语句肯定不同？

不同的SQL语句，对应DAO层，目前看来好像要有不同的方法来实现。

老师，有没有xadmin对应django3.0的版本，配置了一个xadmin结果整个Django虚拟环境都装坏了，删除xadmin源码包也不行，各种报错，如何恢复环境

老师请问如果做批量删除更新和添加的该如何封装BaseDao

老师，3.6版本的pycharm怎么下载？3.8版本好像没有 打包的操作

老师，有个疑问，购物车有两个全选，我给了同一个id，但是用jQuery获取这个id后，只有第一个全选可以实现，难道我要将两个全选分开写么

老师，我按照视频中的代码进行测试，但是报了异常，请问怎么解决？