不能够正常访问The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

这个错误通常发生在你输入了一个不存在的URL。Flask应用程序中的每个URL都对应一个视图函数，当你在浏览器中输入一个URL时，Flask会将该URL与视图函数进行匹配，并执行相应的视图函数来生成响应。如果Flask无法找到与该URL匹配的视图函数，就会出现"The requested URL was not found on the server"这个错误。

因此，你需要检查一下你在浏览器中输入的URL是否正确。在默认情况下，Flask应用程序只有一个根URL("/")，也就是http://127.0.0.1:5000/。如果你希望访问其他URL，你需要在应用程序中定义相应的路由和视图函数。

例如，你可以在应用程序中添加如下代码：

@app.route('/hello')
def hello():
    return "Hello World!"

这个代码定义了一个名为/hello的URL，当你在浏览器中访问http://127.0.0.1:5000/hello时，Flask会执行hello()函数并返回"Hello World!"字符串。

需要注意的是，在Flask应用程序中添加新的路由和视图函数后，你需要重新启动应用程序才能生效。你可以在终端中按下Ctrl+C来停止应用程序，然后重新运行python app.py命令来启动应用程序。

相关问题

The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

As an AI language model, I do not have access to specific URLs or websites. However, if you are experiencing this error message, it typically means that the webpage you are attempting to access cannot be found on the server. This may be due to incorrect spelling or an outdated link. You can try double-checking the URL for any typos or searching for the correct webpage through a search engine.

Not Found The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

As an AI language model, I cannot access URLs or web pages. However, if you encountered this error message while trying to access a website, it means that the server could not find the requested resource. You can try checking the URL for any spelling errors or contact the website's administrator for further assistance.