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Environment: Java8 + aviator5 two point five Introduction to Aviator Aviator is a high-performance and lightweight expression evaluation engine implemented in java language, which is mainly used for dynamic evaluation of various expressions. Now there are many open source java expression evaluation engines available. Why do you need avatar? ...

multi-table queryMulti table query, also known as association query, refers to two or more tables completing the query operation together.Prerequisite: these tables queried together are related (one to one, one to many). There must be an associated field between them. This associated field may or may not have a foreign key. For example: employe ...

Catalogue ​ 1. Load balancing 2. Introduction to Ribbon 3. IRULE 7 default algorithm 4. Project practice 4.1 preparations 4.2. Create a Ribbon service 1. Load balancing Load balancing simply means that users' requests are evenly distributed to multiple services, so as to achieve high availability (HA) of the system. Common load balanci ...

1, What is cross domain? In the front-end field, cross domain refers to that the browser allows to send cross domain requests to the server, so as to overcome the limitation that Ajax can only be used in the same source. What is homology strategy? Homology policy is an agreement. The browser was introduced by Netscape in 1995. It is the most ...

Test Hooks' proficiencyWhy can't Hooks be used in for loops and if statementsReact.memo,React.useCallback,React. The role and comparison of usememoThe value in useState is an object. If you change the value in the object, will the component render? If you use react It's wrapped in memo()What is the (Implementation) principle of Hooks?What is th ...

(1) : method of comparing objects There are a lot of concepts. Just have a look: 1: ReferenceEquals: Object.ReferenceEquals(left, right) static method: it can be seen from the name that it is used to compare whether they are the same reference. We should never override this method. It always returns false for the comparison of value type ob ...

explain This blog is updated every Friday. Based on the original Elasticsearch installation, this paper adds plug-in x-pack user authority authentication and Kibana page management to enrich the use scenarios of Elasticsearch. The installation is divided into three levels Normal installation, only Kibana is enabled, and x-pack is not ...

Java basic syntax Note summary from If you need source code or answer questions, please contact QQ: 1876504704 1, Comments, identifiers, keywords notes Writing notes is a very good habit Comments are not executed. They are for the person who writes the code There are three types of notes: Single line comment: "/ /" Multiline ...

Introduction to basic use The service provider writes the implementation class based on the interface Keep Dubbo service interface (including registry address, protocol name and port) with Spring configuration The consumer cooperates with Spring and references the dubbo service interface (including: configuring the address of the regist ...

catalogue Monitor introduction Liquid crystal display Basic parameters of display Liquid crystal control principle Introduction to ILI9341 LCD controller Signal line and 8080 timing of LCD FSMC of STM32 is used to simulate 8080 interface timing Introduction to FSMC Memory controller Clock control logic FSMC analog 8080 timing Softwa ...