Programmer Group

1, Java Memory Model JMM is the Java Memory Model, which defines the abstract concepts of main memory and working memory. The bottom layer corresponds to CPU register, cache, hardware memory, CPU instruction optimization, etc. JMM is reflected in the following aspects: 1. Atomicity - ensure that the instruction will not be affected by thread co ...

java implementation of excel import and export and solution Because of the company's business requirements, excel uses the MultipartFile class to import and export tables , here are some key codes. I hope they can help //To obtain the input stream of excel file, it must be. Xlsx suffix. If it is xlsx suffix, use HSSFWorkBook X ...

1. Definition Provides a way to access an aggregate object without exposing the internal representation of the object, alias cursor. The iterator pattern is an object behavior pattern. 2. UML class diagram Abstract container role (Aggregate): it is responsible for providing an interface for creating a specific iterator role, generally an ...

Lamda expression λ It is the eleventh letter in the Greek alphabet, and its English name is Lambda.Why use lambda expressions: 1. Avoid too many anonymous inner class definitions. 2. It can make your code look very concise. 3. Remove a pile of meaningless code, leaving only the core logic.lambda expressions are essentially functiona ...

preface:         In the process of specifically interpreting the functional principles of the core classes of JobTriggerPoolHelper, please familiarize yourself with the basic principles of ThreadPoolExecutor, volatile, ConcurrentMap, AtomicInteger, etc. at the same time, please consider the problems of JobTriggerPoolHelper ...

front word : \textcolor{green} {Preface:} preface: 💞 In the previous article, we learned what Mybatis is and also wrote our first Mybatis program. Next, let's take a look ...

Technology stack: java+springboot+rabbitmq In this article, let's discuss the design scheme of merchant transaction result notification. Students who do payment know that some transaction types are asynchronous transactions, that is, when the transaction message is sent to the bank or a third-party payment channel, the other party does not r ...

The number of classes has increased - > need to manage classes - > package (can be understood as a folder). Package and import appear at the same time. Write package first and then import. There can only be one package and multiple imports. is-a (generalized) inheritance implementation has-a (inclusive) combination aggregation Associati ...

Microservice Architecture Foundation (II) To be continued Continue the previous basic project for expansion Load balancing and service invocation Ribbon Ribbon local load balancing client & nginx server load balancing difference Nginx is server load balancing. All client requests will be handed over to nginx, and then ngin ...

preface Our last article introduced the Servlet request and response interface. In this article, I will introduce the simulation of the educational administration system based on the current knowledge. Its functions include user registration, user logout, user information modification and user query. It will use the knowledge of JDBC, DA ...