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Basic process of Python crawler web page:First, select some carefully selected seed URL s.Put these URLs into the URL queue to be fetched.Read the URL of the queue to be crawled from the URL queue to be crawled, resolve DNS, obtain the IP of the host, download the web page corresponding to the URL and store it in the downloaded Web page library ...

11.1 role of generics 11.1.1 concept of generics The so-called genericity is to allow an identifier to represent the type of an attribute in a class or the return value and parameter type of a method when defining a class or interface. This type parameter will be determined when used (for example, inheriting or implementing this interface, d ...

Recently, when consulting some questions, some small partners found that many small partners did not know "opportunism" in the process of practical operation. That is the so-called "laziness". The laziness mentioned here is not the traditional laziness and trickery, but learning to "use tools". You should know that ...

Basic operation of file Open / close file The built-in function open can open a file under the specified path and return a file object There are two most commonly used parameters for open. The first parameter is the file name (absolute path or relative path), The second is the opening mode, 'r' /'w '/'a' /'b ', which means read (default) / ...

Basic concepts Edit distance issue: It is difficult to edit the distance problem, but the solution is very beautiful, and it is also a rare practical algorithmEdit the distance usage scenario: For revising the misplaced content of the article The article can only be modified by 20 words, and supports adding, deleting and replacing oper ...

java process control I User interaction Scanner scanner object Scanner class to get user input Basic grammar //Create a scan object to receive keyboard data Scanner scanner=new Scanner(System.in); System.out.println("use next Reception mode:"); //Judge whether the user has entered a string if (scanner.hasNext()){ //Receive in next mode ...

Template method pattern purpose Template method: when the steps are determined and fixed, the details of each step are differentiated in multiple subclasses through polymorphic mechanism, which is the effect that template method can achieve; classification Template method mode: it belongs to behavior mode in design mode; Specific examples ...

From: Micro reading https://www.weidianyuedu.com/content/0117397506434.html 1, Use of asynchronous requests in Spring Boot** 1. Asynchronous request and synchronous request Synchronization request Asynchronous request Features: you can first release the threads and related resources allocated by the container to the request, reduce ...

Preface: we often use the static keyword in Java, so many times we don't know when to use the static keyword, and what is the relationship between the internal logic used by the static keyword and the object? So today we'll talk about the static keyword and understand it in essence. Static: static static can be used to modify: attributes, me ...

The following are my notes on watching the Java learning video of shangsilicon valley   Enumeration class Class has only a limited number of objects, which is uncertain. Examples are as follows: Monday, SundayGender: man (male), woman (female)Season: Spring Festival... WinterPayment methods: Cash (cash), WeChatPay (WeChat), Alipay (Al ...