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selector To apply CSS styles to specific HTML elements, you first need to find the target element. In CSS, the style specification that performs this task Then the part is called a selector (selector). CSS base selector 1. Wildcard (global) selector Wildcard selectors are indicated by "*", which is the most extensive of all select ...

In microservices, for high availability, the same service is often deployed in cluster mode, that is, there are several same services at the same time, and the core of gray level is routing, which calls the target service line through our specific strategy 1 Introduction to gray routing Grayscale publishing (also known as Canary Publ ...

Write in front Recently, in project development, easy excel technology was used to analyze and write excel, so today I share with you how to use easy excel technology to analyze Excel files Introduction to Easyexcel Technology Easyexcel technology is developed on the basis of poi. It is the optimization and promotion of poi '. Compared with ...

1, Basic structure of three frames 1. Why is a framework needed Note: if the projects in the production environment are developed from scratch (from the bottom), it is too difficult and the development efficiency is extremely low. Therefore, in order to quickly deploy the project online, some specific functions are encapsulated in advanced. ...

Content of this paper Problems solved by DockerDocker discussionDocker common commandsBrief description of Docker image, network and data volumeDockerFileDockerComposeContainer orchestration Swarm and k8s Note: the content of this article comes from the Docker video summary of crazy God talking java in station B. 1, Why did Docker appear &e ...

prefaceIn the process of iOS development, de reprocessing is sometimes used, that is, removing duplicate elements or numbers, and then sorting. This uses the set (NSSet). In fact, it is a hash table that uses the hash algorithm to find the elements in the set.The similarities between sets and arrays are the addresses where different elements ar ...

concept Do you understand the database index? Generally speaking, the underlying data structure There are two common mysql structures: Hash index, B+ Tree index and full text index. We use innoDB engine, The default is B + tree. Differences between the two structures: The bottom layer of hash index is hash tab ...

catalogue 1, I2C protocol 1. What is the I2C protocol 2.I2C physical layer 3.I2C protocol layer 4. Two ways of I2C - hardware I2C and software I2C 2, Data collection using AHT20 1. Learn about AHT20 chip 2. Connect hardware 3. Code 3, Summary 4, References 1, I2C protocol 1. What is the I2C protocol I2C communication protocol (In ...

This article is excerpted from "design patterns should be learned this way"1. Application scenario of intermediary modeIn real life, the existence of intermediaries is indispensable. Without intermediaries, we can't communicate with distant friends. Each colleague object will reference each other. If each object interacts with multipl ...

##Database connection pool       The code logic in the previous section is equivalent to opening a restaurant, recruiting a waiter connection to connect to the database service when the guest comes, and firing the close when the guest leaves   So we should recruit a few employees. It's a great waste of resources   &n ...