Learn from python-day018 --- from Python distributed crawler to create search engine Scrapy

In section 341, Python distributed crawler creates search engine Scrapy elaboration - writes spiders crawler file to retrieve content in a circular way - the meta attribute returns the specified value to the callback function - Scrapy built-in Image Downloader Write spiders crawler file to retrieve cont ...

Posted by yasir_memon on Mon, 17 Feb 2020 02:32:19 -0800

Drawer of drawer

Drawer (drawer component) 1. Overview Scalfold is a common layout Widget used by the Flutter MaterialApp. It accepts a Drawer attribute and supports the configuration of the Drawer. It can pull out the navigation panel from the side bar. The advantage is to fold up some function menus. Generally, th ...

Posted by Asperon on Mon, 17 Feb 2020 01:11:53 -0800

Spring -- Junit test tool, property injection method, annotation

1. Junit test tool Junit is a unit testing framework for Java programming language Common comments are: @BeforeClass: indicates that the method using this annotation is executed before the test class is called. This annotation can only be declared once in a test class, and the method corresponding to ...

Posted by Sanoz0r on Sun, 16 Feb 2020 23:18:51 -0800

HTML+JS reading form data

HTML+JS reading form data Expected effect Code Analysis Result display Expected effect When a form is submitted, it is usually necessary to verify the data validity of the form. The premise of verifying the data is to read the data of the form elements. As shown in Figure 1 below, when clicking ...

Posted by kurios on Sun, 16 Feb 2020 05:00:27 -0800

The key function selector of jQuery

Selector is the core of jquery The object returned by jquery selector is jquery object, which does not return undefined or null, so it is unnecessary to judge   Basic selector: ID selector $("" Id ") element selector (label selector) $("label") such as $("div") Get the specific label, and use the way of array ...

Posted by jesse26 on Sun, 16 Feb 2020 02:54:35 -0800

Dynamic agent, annotation, classloader learning

Record learning content Today's main learning: dynamic agent, annotation, classloader 1, Dynamic agent Role: enhance a method. There are three ways to enhance an object: 1. Inherit, override method after inheriting parent class. Advantages: simple, easy to implement, can inherit the class after rewritin ...

Posted by mizkit73 on Sun, 16 Feb 2020 02:50:18 -0800

Python - Object Oriented Advancement

isinstance and issubclass isinstance(obj,cls) checks if obj is an object of class CLS class Foo(object): pass obj = Foo() isinstance(obj, Foo) issubclass(sub, super) Checks if the subclass is a derived class of the super class class Foo(object): pass class Bar(Foo): pass issubclass(Bar, Foo) reflex 1 What is reflecti ...

Posted by m!tCh on Sat, 15 Feb 2020 11:46:35 -0800

Analysis of bootstrap switch control

Basic example: <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta name=viewport content="width=device-width, initial-scale=1"> <title>bootstrap Example of switch</title> <link href="bt/css/bootstrap.min.css" rel="stylesheet" /> <link href ...

Posted by JChilds on Sat, 15 Feb 2020 07:17:12 -0800

Spring boot integrates WEB Development -- processing JSON return data

1. Use the default json to convert HttpessageConverter At present, JSON is the mainstream front and back end data transmission mode. In spring MVC, HttpMessageConverter is used to support the conversion of JSON, and the relevant configuration is further simplified in spring boot. pom.xml <dependency> <groupId>org.springframework.b ...

Posted by fazlionline on Sat, 15 Feb 2020 02:14:09 -0800

Dubbo: Deep understanding of the core model of Dubbo Invoker

1. Introduction of Invoker in Dubbo Why is Invoker the core model of Dubbo? Invoker is an entity domain in Dubbo, that is, it really exists.Other models approach it or convert it, and it also represents an executable from which invoke calls can be made.At the service provider, Invoker is used to invoke the service provider class.On the service ...

Posted by jini01 on Fri, 14 Feb 2020 23:45:09 -0800