Programmer Group

1. Preliminary cognition of class and object [object oriented concept]: 1. Object oriented is a way of thinking and an idea. For example: concepts and examples. Theory and practice. Name and reality, etc 2. Class is the general name of a class of objects. An object is an instance of this kind of materialization. 3. The benefits of obj ...

Example 001: digital combination Title: there are four numbers: 1, 2, 3 and 4. How many three digits that are different from each other and have no duplicate numbers? How much is each? The program analysis traverses all possibilities. Please shave off the duplicates. num = 0 for a in range(1, 5): for b in range(1, 5): for c in ra ...

Build an instance based on memcache: web(php) host: 192.168.181.6 redis host: 192.168.181.5 mysql host: 192.168.181.4 First, close the firewall of the three hosts systemctl stop firewalld systemctl disable firewalld sed -i 's/enforcing/disabled/'/etc/selinux/config setenforce 0 Synchronization time yum -y install ntp ntpdate ntpdat ...

1. Introduction to characteristics 1.1 general Sometimes, we will encounter some specific needs, that is, to strengthen the functions of some classes (or objects) without affecting the current inheritance system. For example, there are monkeys and elephants. They all have names, ages and eating functions, but some monkeys are trained by the c ...

1. Description You can use JPA entities as process variables, allowing you to: Update the existing JPA entity based on process variables that can be filled in the userTask or generated in the serviceTask.Reuse existing domain models without having to write explicit services to get entities and update valuesMake a decision based on the attribu ...

Namesrv for RocketMQ Source Analysis Source analysis is more content points, of course, we can not read all the source code of RocketMQ, so we interpret the core, focus source code. The source code to be interpreted is as follows: 1,RocketMQ Overall architecture of source analysis 2,RocketMQ Source Analysis NameServer 3,RocketMQ Source Analy ...

  preface This article will explain the offset analysis function + over() through an example 1, Concept of offset analysis function lag(col,n,default): used to count the value of the nth row up in the group. The first parameter is the column nameThe second parameter is the nth line up (optional, not filled in, default to 1)The third ...

New bee mall project notes 1. Start the project and access the api online documentation http://localhost:8080/swagger-ui.html [the external chain image transfer fails. The source station may have an anti-theft chain mechanism. It is recommended to save the image and upload it directly (img-ge9fugsh-163811491017) (C: \ users \ Chen \ appdata ...

catalogue   (no js authority, damn it, I remember this account qaq) brief introduction I recently started to contact git team development projects, because I am not familiar with git, so I make this essay to prevent forgetting. If there is any mistake or mistake, please advise. Record a teaching game website using git https://learngitbranc ...

aggregate Java has many collection classes, which are divided into two main categories Sets are mainly two groups (single-column set, double-column set)The Collection interface has two important subinterfaces, List and Set, whose implementation subclasses are single-column collectionsThe implementation subclass of the Map interface is a t ...