Programming VIP

Use of Easypoi package preface Recently, my boss asked me to implement an import and export function. Because this project is a very old maintenance project, the JExcel API package is still used for the import and export of excel. Although I have encapsulated the tool class, I still feel very troublesome ~, especially the title, which keeps a ...

1, Generic overview and basic usage A: Overview of generics: java generics is essentially a parameterized type, that is, the operated data type is specified as a parameter (type parameter). This parameter type can be used in the creation of classes, interfaces and methods, which are called generic classes, generic interfaces and generic m ...

catalogue Foregoing Structure of container Singleton set implementation class List--ArrayList Capacity expansion mechanism of ArrayList Add element Get element Replace element Delete element Find the location of the element Find element exists List size Judge whether the list is empty Convert to array clear list Get list iterat ...

The official account: yk Kun Emperor The background replies to the invoice identification and obtains all the source code 1. Scene description 2. Prepare the environment 3. Extract content 1. Withdraw invoice amount 2. Name of the seller 3. Extraction of taxpayer identification number 4. Drawer 4. Batch identify invoices and save them to ...

Static keyword 1. Static global variable Static modifies a global variable to make it a static global variable. This variable is stored in the static storage area and can only be used in this file. Therefore, other files can also define variables with the same name without conflict. 2. Static local variable It refers to static modifying ...

preface   we learned the basic Operation rules Of course, our operators are indispensable in the process of operation, including "+", "-", "*", "/", which we are familiar with. And some special operators of Java language, such as self increasing, self decreasing, logical operators, etc. I w ...

The importance of functions in programming is self-evident, so this article will briefly describe some contents related to functions. What is a function Function, translated as a method or function. The main function achieves a certain purpose by calling a user-defined function or a function in the function library, or obtains the desired dat ...

1, What is reflection? Reflection means that in the running state, all properties and methods of any class can be known, and any method of any object can be called. This function of dynamically obtaining information and dynamically calling object methods is called the reflection mechanism of java language. Reflection is very powerful, with ...

preface   continue to learn Java object-oriented today, and understand what is method overloading, what is method rewriting, and what is the difference? Know the keywords this and super and understand their usage.   I hope it can be helpful to your study! Tip: the following is the main content of this article, and the Java ...

As a top distributed open source project, ZooKeeper is widely used. Dubbo and Kafka are well-known open source projects. I've only heard of it before and haven't studied it carefully. Today, I'll take you to learn about ZooKeeper, mainly from three aspects: ZooKeeper installation, visualization tools and application. I hope it will be helpful t ...