Programmer Group

catalogue Objectives: 1. Variable overview 1.1 what are variables   2. Use of variables 2.1 declare case variables 2.2. Assignment 2.3. Initialization of variables Case: use of variables: 3. Syntax extension of variables 3.1 updating variables 3.2 declaring multiple variables 3.3 special cases of declared variables 4. Naming s ...

Tips: In the previous article, I shared how to jump to a page. Today we will continue to talk about click events in detail. Tomorrow we will continue to share double-click events and long-click events   1. Click event There are four kinds of click events in HarmonyOS. Next, let's introduce the four kinds of click events and how to i ...

1, Abstract class 1. A class containing abstract methods is called an abstract class 2. Abstract methods. A method without specific implementation is modified by abstract eg: abstract class Shape { public int a; public void func(){ System.out.println("test"); } public abstract void draw(); } ·Abstract is ...

1. Object oriented (1) Object oriented understanding Object-oriented is based on object, which mainly emphasizes object. Face object is an idea to solve problems, which mainly depends on the interaction between objects to complete a thing (2) Object oriented features Object oriented is a common idea, which is more in line with people's t ...

Record the learning content. If there are mistakes, thank you for correction, communicate with each other and make progress together ThreadLocal Summary: In the heap memory, there is a thread shared hash table ThreadLocalMap, which can be used to transfer parameters in the thread, such as user information, application information and other b ...

In some important information notification scenarios, users need to receive and pay attention to the information. The synchronous push of SMS + voice notification can solve this problem. SMS notification + voice notification of the same content are sent synchronously Push the voice notification of the same content synchronously while pushing ...

mybatis supports different databases. The specific access to the database is the driver jar package provided by different database manufacturers. For example: mysql-connector-java.jar of MySQL The jar s provided by different manufacturers are also implemented based on the interface in the java.sql package under the JDK For example, different d ...

1. Algorithm complexity: The time complexity and space complexity of the algorithm are collectively referred to as the complexity of the algorithm. Time complexity: time complexity refers to the calculation workload required to execute the algorithm; Space complexity: it is a measure of the amount of storage space temporarily occupied by ...

catalog:What is a queue?What are the characteristics of queues?Queue noun descriptionDetailed explanation of queue typesQueue operationText:What is a queue?Queue is a special linear table, which is only allowed at the front of the table( front)Delete, but at the back end of the table( rear)Like the stack, a queue is a linear table with restrict ...

2, Mycat global serial number Mycat can guarantee id uniqueness in the following ways: 1) Local file mode 2) Database mode 3) Timestamp mode 4) ZKID generator 5) ZK increment ID 4 and 5 are recommended In the above 5 methods, the global serial number configuration should be enabled in the server.xml file and the autoIncrement attribute of the l ...