Programming VIP

Demand background There are several reasons why multiple consumer instances need to be deployed in the project: Based on the reliability improvement requirements of the system. Especially for the container deployment scheme based on micro service architecture, multi instance deployment of micro service is the basic requirement to ensure the re ...

1, Transaction Basics 1. Transaction definition 2. Four characteristics of transaction Atomicity Transaction is the logical work unit of database. All operations included in transaction are either done or not done at all.Consistency The result of transaction execution must be to change the database from one consistency state to another. ...

java Basics 4, Process control 4.1. Basic structure Sequential structure The command line is executed sequentially Branch structure (select structure) Different results can be obtained by selecting different execution processes according to conditions category Single branch statement ​ if–else Multi branch statement ...

PS: This article is a reprint of the article. It will be more readable to read the original text. There is a link to the original text at the end of the articlecatalogue1. Cued binary tree1. Cued binary treeBefore introducing the clue binary tree, let's take a look at a case. I'll draw a binary tree first, as shown in Figure 1:pictureIf we trav ...

1, Threads and processes In programs that do not use multithreading, the program has only one main thread, and our program is top-down according to the code. In multithreaded programs, other threads run simultaneously with the main thread. As shown in the figure: Next, we introduce related concepts Speaking of process, we have to say pro ...

Official concept: AOP, that is, aspect oriented programming, can be said to be the supplement and improvement of OOP (Object Oriented Programming). OOP introduces the concepts of encapsulation, inheritance and polymorphism to establish an object hierarchy, which is used to simulate a set of public behaviors. However, OOP allows developers to de ...

1.Spring Cloud learning Feign declarative service invocation Hystrix fuse Gateway gateway 2.Feign 2.1 feign general • Feign is a declarative REST client, which uses interface based annotation to facilitate client configuration. • Feign was originally provided by Netflix, but does not support spring MVC annotation. Later, it was enca ...

Holding fireworks to make a living, poetic to seek love catalogue 1. Principle introduction 2. Detailed steps 2.1 data acquisition 2.2 data center (Standardization) 2.3 finding covariance matrix 2.4 calculate eigenvalues and eigenvectors of covariance matrix 2.5 determining the number of principal components 2.6 calculation of princi ...

ES getting started HTTP Install ES Download from ElasticSearch official website , take the latest version as an example, elasticsearch-7.17.0-windows-x86_64.zip Unzip the compressed package, enter the bin directory in elasticsearch, and double-click elasticsearch Bat run, enter in the browser http://localhost:9200 , press enter, and the ...

catalogue @SpringBootApplication Spring Bean related @Autowired @Component,@Repository,@Service, @Controller @RestController @Scope @Configuration Handling common HTTP request types GET request POST request PUT request DELETE request PATCH request Front and rear end value transmission @PathVariable and @ RequestParam @RequestBod ...