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2.4 use optimistic lock to place orders concurrently Important: When multiple users initiate an order request for the same commodity at the same time, first query the commodity inventory and then modify the commodity inventory, there will be resource competition, resulting in abnormal final results of inventory. 2.4.1. Concurrent order probl ...

subject http What are the common status codes? http common header What are there? What is? Restful API Describe it http Caching mechanism for (important) Answer from the perspective of forced caching and negotiated caching. Flowchart remember. http status code Status code classification 1xx The server received the request 2xx Reques ...

1, ES6 grammar guide After the back-end project is built, the front-end page is next. But before that, some preparations are needed. We need to learn the Syntax Standard of ES6. What is ES6? ECMAScript version 6 standard. 1. What is ECMAScript? Let's take a look at the development of the front end: web1.0 era: The original web page is mai ...

What are css custom attributes It's officially called custom attribute, but I'm used to calling it variable. In short, it's a CSS attribute that developers can name and use independently How are CSS variables different from those in the preprocessor? CSS variables are CSS properties directly available in the browser, while variables in prepr ...

Template engine and Freemarker The goal of the template engine is "data + template = result" Template engine effectively "decouples" data from presentation template engine Mainstream template engine Java Server Page(JSP)FreemarkerBeetle Freemarker Freemarker is a free and open source template engine technology Free ...

Spring MVC rest style REST (Representational State Transfer) is the most popular software architecture style at present REST refers to a set of architectural constraints and principles. Applications or designs that meet these constraints and principles are RESTful REST features: Resources: all things on the Internet can be abstracted as ...

Basic use Gin is a high-performance golang web framework. Its code is actually very few. Compared with spring, understanding gin is really chopping melons and vegetables Let's take a look at the basic usage of gin import "github.com/gin-gonic/gin" func Init() { r := gin.Default() initRoute(r) r.Run() } func initRoute(r *gin.Engine) { r ...

Responsive layout of mobile WEB development 1.0 principles of responsive development 1.1 principles of responsive development Media query is used to set the layout and style for devices with different widths, so as to adapt to different devices. Division of equipment: Those less than 768 are ultra small screens (mobile phones)The betwe ...

1. Scenario Display File upload is often used in the development process; This article will take the spring boot as an example, how to receive the file request from the front end; It is more convenient to upload files using plug-ins. Here I use webuploader 2. Front end code Step 1: prepare the web loader plug-in and put it into the project; ...

HelloWorld 1. Import jar package 2. Configure web XML file <!-- to configure DispatcherServlet --> <!-- The front controller of this Spring Web application, responsible for handling all application requests --> <servlet> <servlet-name>springDispatcherServlet</servlet-name> <servlet-class>org.springfra ...