Programmer Group

architecture design We can divide the functional architecture of Mybatis into three layers: API interface layer: interface APIs provided for external use. Developers use these local APIs to manipulate the database. As soon as the interface layer receives the call request, it will call the data processing layer to complete the specific da ...

prefaceFor Android development, after working for a few years, we have to advance or change careers directly. If you are still working on Android and want to improve your understanding of the Framework, it is an essential process. Let's start today's topic.As we know, for any programming language, the entry is generally the main function.Where ...

Basic operation of MongoDB learningThe aggregation operation of mongo is similar to the query of mysqlSQL operations / functionsmongodb aggregation operationwhere$matchgroup by$grouphaving$matchselect$projectorder by$sortlimit$limitsum()$sumcount()$sumjoin$lookupThe following examples are compared with sqlThe following is a basic structure for ...

1, Object description Source code note: the Object class is the Root node of the hierarchical relationship of all classes. As the superclass of all classes, including arrays, it also implements the methods of this class. Note that what is said here is very clear, referring to the class level. Therefore, there is a common saying in Java that e ...

  preface This article will explain the offset analysis function + over() through an example 1, Concept of offset analysis function lag(col,n,default): used to count the value of the nth row up in the group. The first parameter is the column nameThe second parameter is the nth line up (optional, not filled in, default to 1)The third ...

1, Small and problems 1. Title Description: In an array, the numbers on the left of each number that are smaller than the current number are added up, which is called the small sum of the array. Find the small sum of a given array. 2. Example: The array is: [1,3,4,2,5] 1 the number smaller than 1 on the left: No 3 the number smaller than ...

In daily development, there are always various interfaces. Front and rear end data transmission interfaces, third-party service platform interfaces. The front and rear data transmission interfaces of a platform generally communicate in the Intranet environment and use the security framework, so the security can be well protected. This article f ...

  0x01: byte stream Byte stream base class 1. InputStream InputStream: the base class of byte input stream. The abstract class is a superclass representing all classes of byte input stream. Common methods: // Reads the next byte of data from the input stream abstract int read() // A certain number of bytes are read from the input st ...

Content index Class loader Class loading system Class loading Dynamic class loading Dynamic class overloading Custom class overload Class load / reload example Java allows you to dynamically load and reload classes at run time, but this function is not as simple and direct as people want. This article will explain how to load and overload cl ...

Introduction ​​ Have nothing to do: The excrement shoveling officer made a hamster toy for the cat owner with waste cardboard boxes. Look, the owner has a lot of fun I knocked it out - eh, why, why are there two? Isn't it exciting? This is a good chance to improve your relationship with the master! ​​ Ha ha ha! After reading the above ...