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 19.  19. One to one and one to many association queries?     <mapper namespace="com.lcb.mapping.userMapper"> <!--association One to one association query --> <select id="getClass" parameterType="int" resultMap="ClassesResultMap"> select * from class c,teacher t where c.teacher_id=t.t_id ...

Alternate bit binary number Given a positive integer, check whether its binary representation always alternates 0 and 1: in other words, the numbers of adjacent two digits in the binary representation will never be the same. Get data by bit and XOR class Solution { public: bool hasAlternatingBits(int n) { int a = n & 1; ...

Analysis of various applications of pointer and real interview questions of large factories preface Most of the pointers learned by beginners or ordinary colleges and universities are simple, that is, we understand that the pointer is an address. We can operate the address content through dereference operation, which is often limited ...

Why use CDN When more and more components are introduced, use the app packaged by webpack JS file is easy to become too large, which is very unfriendly to the first screen loading. The JS code using the third-party resources of CDN will no longer be packaged into the JS package of local services. Reduce the volume of local JS package and imp ...

Review the basic content of threads Program: static code installed on the hard disk. Process: the running program is the space unit of memory allocated by the operating system. Thread: it is the smallest execution unit in the process and the scheduling unit of cpu. Threads depend on the process. Create thread Thread class inherits threadClas ...

The essence of annotation When talking about the essence of annotation, the simplest way is to decompile. See the essence. The code is as follows: import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; @Retention(RetentionPolicy.RUNTIME) public @interface Foo{ String[] value(); boolean bar(); } Use the ...

I Interview questions and analysis 1. Today's interview question What search and insert algorithms do you know? What is half search? Talk about the code implementation of binary search method 2. Topic analysis Today's topic is mainly to investigate our mastery of commonly used algorithms in development, especially search algorithms ...

📑 Content of this article: SpringBoot two brush automatic assembly principle - in fact, it is really as simple as you think~ 📘 Article column: Principle and project development of SpringBoot microservice 🎬 Last updated: January 22, 2022 SpringBoot two brush automatic assembly principle - in fact, it's really as simple as you think~ 🙊 Perso ...

Object advanced Object creation mode Object constructor mode First create an empty Object object, and then dynamically add properties / methods var p = new Object() p = {} p.name = 'Tom' p.age = 12 p.setName = function (name) { this.name = name } console.log(p.name, p.age) p.setName('Bob') console.log(p.name, p.ag ...

preface Now it is more and more difficult for Android junior and intermediate development engineers to find a satisfactory job. Of course, those with strength do not worry about a good job. If you happen to be a junior and intermediate engineer who wants to advance the direction of audio and video or is interested in NDK technology, you must b ...