Programmer Group

What is automatic packing and unpacking? ​Very simple, you can see the packing and unpacking process in the following two sentences of code//Automatic packing Integer total = 99; //Automatic unpacking int totalprim = total;To put it simply, boxing is to automatically convert the basic data type to the wrapper type; Unpacking is to automatically ...

The data system in the group cannot meet the performance requirements when undertaking a business requirement, so some optimizations are made for this scenario, and an article is written here for records. The business scenario is as follows: the caller obtains hundreds of characteristics of a user at a time (characteristics can be understood a ...

Objectives of this section Understand what a collection framework isUnderstand the meaning of learning set frameworkMaster the relevant interfaces and common implementation classes of the collection frameworkUnderstand what to learn in the next stage 1. Introduction Official course The Java Collection Framework, also known as the container c ...

In the previous analysis, the Spring Framework has been committed to solving a problem, that is, how to make bean management easier, and how to make developers pay less attention to the configuration of some basic beans, so as to realize automatic assembly. Therefore, the so-called automatic assembly is actually how to automatically load beans ...

background   Yes, if you want to search the List collection, you can use your own contains/ indexOf method to find elements before Java 8, but only complete elements, not fuzzy search or user-defined search. At this time, you can only traverse. But now it's 2021. Are you still searching for List collection elements in the traditional way of ...

One background With the rapid development of the Internet industry, web-based business and processes become more cumbersome and iterative faster. Traditional manual testing can not meet the market demand. In order to reduce the labor cost of regression, rapid iteration and automatic testing are the inevitable trend. This article mainly int ...

1. What is SPI1. BackgroundIn the object-oriented design principle, it is generally recommended to program based on the interface between modules. Generally, the caller module will not perceive the internal implementation of the called module. Once the code involves specific implementation classes, it violates the opening and closing principle. ...

Visitor mode brief introduction The purpose of visitor pattern is to encapsulate some operations imposed on some data structure element. Once these operations need to be modified, the data structure that accepts the operation can remain unchanged. Intent: mainly separate data structure from data operation. It mainly solves the problems of s ...

What is automatic packing and unpacking? ​ Very simple, you can see the packing and unpacking process in the following two sentences of code //Automatic packing Integer total = 99; //Automatic unpacking int totalprim = total; To put it simply, boxing is to automatically convert the basic data type to the wrapper type; Unpacking is to automati ...

1. File class    file class represents platform independent files and directories under java.io package, that is, if you want to operate files and directories in the program, you can use file class. It is worth noting that both files and directories are operated by file. File can create, delete and rename files and directories, and f ...