android

Detailed redis persistence

Must our Redis use data persistence? If our Redis server is only used as a cache, and all data stored in Redis is a backup synchronized from other places, then there is no need to enable the option of data persistence. Redis provides the ability to automatically persist data to the hard disk on a regular basis, including two schemes, RDB and AOF. The two schemes have their strengths and weaknesses respectively, and can work together to ensure data stability. vRedis persistence Redis provides a

Grace

schedule 19 min read

android

Spring recruit interview review, sort out prototypes and prototype chains~ JS Plan

Preface Starting from a Didi interview question, it is a very basic question about prototypes and prototype chains, but it is also necessary to clearly understand the relationship between prototypes and prototype chains in order to answer better. After all, you may have a clear idea. It's important. Not much nonsense, let's look at the topic first: Object .prototype.a = "jing1" ; Function .prototype.a = "jing2" ; function Preson () {}; Var P = new new preson (); Console .log (PA); Console .log

Lincoln

schedule 15 min read

android

R language generalized additive models (GAMs) analyze and predict CO2 time series data

Original | tecdat.cn/?p=20904   Source  |  Topend Data Tribe Official Account   Many data in environmental science are not suitable for simple linear models and are best described by generalized additive models (GAM). This is basically an extension of the Generalized Linear Model (GLM) with a smooth function . Of course, when you use smooth terms to fit a model, many complicated things may happen, but you only need to understand the basic principles. theory Let 's start with

Bryce

schedule 10 min read

android

21-minute MySQL introductory tutorial

Introduction to MySQL related concepts MySQL is a relational database (Relational Database Management System). This so-called "relational" can be understood as the concept of "table". A relational database consists of one or several tables, as shown in the figure: Header : the name of each column; Column (row) : a collection of data with the same data type; Row (col) : Each row is used to describe the specific information of a certain person/thing; Value (value) : the specific information of the

Hudson

schedule 18 min read

android

Dagger2 and its application on SystemUI

Just as humans need to live in groups, processes and threads in the programming world also need to communicate. Their communication depends on the relationship between modules and files. How to quickly figure out and build this relationship, and at the same time reduce mutual dependence, requires developers to think carefully. We call this requirement Dependency Injection (DI, Dependency Injection). This programming technique has a long history. Before I talk about it, I want to briefly review

Emily

schedule 13 min read

coder_life

iOS application internationalization tutorial (2014 version)

Article source: www.cocoachina.com/industry/20... This article was originally written by Sean Berry and updated for iOS 7 by Ali Hafizji . Developing a great iOS application is an amazing thing, but there is more to do than good code, gorgeous design, and intuitive interaction. To be in the forefront of the App Store rankings also requires timely product marketing, the ability to expand the user base, practical tools, and the technology to acquire users as widely as possible.   For many dev

Faith

schedule 16 min read

coder_life

[Java] Relearn Java- Enumeration

What can enumeration do Suppose we now want to express the week, in order to avoid the appearance of magic values, we might write a constant class: package com.tea.modules.java8.enums; /** * com.tea.modules.java8.enums <br> * Use abstract classes to express constants to prevent tampering * @author jaymin * @Since 2021/6/9 */ public abstract class WeekConstant { /** * on Monday */ public static final Integer MON = 1 ; /** * on Tuesday */ public static final Integer TUE = 2 ; /** * on Wednes

Dominic

schedule 9 min read

coder_life

Hey, I don't believe it, is Java IO so difficult?

1. IO stream 1.1 Introduction to IO Stream I is input, which means input. o is output, which means output. Stream refers to the transmission of data. The literal meaning of Java IO: the input and output of data is realized through the java programming language. This refers to file read and write operations. So, with regard to reading, where does the data come from? Regarding writing, where is the data written? Read : Load data from the hard disk to the memory, for example, view txt files through

Miles

schedule 15 min read

coder_life

In-depth analysis of HandlerMapping of the nine major components of SpringMVC

Earlier, I shared with my friends a general initialization process of SpringMVC and general request processing process. In the request processing process, nine major components are involved, namely: HandlerMapping HandlerAdapter HandlerExceptionResolver ViewResolver RequestToViewNameTranslator LocaleResolver ThemeResolver MultipartResolver FlashMapManager I believe that these components are more or less involved in daily development. If you are unfamiliar with these components, you can reply to

Cora

schedule 30 min read

coder_life

[Image segmentation] Image segmentation matlab source code based on ant colony optimization fuzzy clustering

Ant Colony Algorithm Introduction Ant colony optimization (ACO), also known as ant algorithm, is a probabilistic algorithm used to find optimized paths in the graph. It was proposed by Marco Dorigo in his doctoral dissertation in 1992, and was inspired by the behavior of ants finding paths in the process of searching for food. Ant colony algorithm is a simulated evolutionary algorithm. Preliminary research shows that the algorithm has many excellent properties. Aiming at the problem of PID contr

Jesse

schedule 16 min read

dev_tools

Flutter study notes

Project directory flutter_app android # Android directory build # build directory ios # iOS directory lib # Development directory (equivalent to src directory) | main.dart # Entry file (equivalent to index.js) test # test directory .gitignore # When Git commits, set to ignore file content pubspec.lock # Project dependency lock information (equivalent to package-lock.json in npm) pubspec.yaml # Project dependency configuration (equivalent to package.json in npm) Copy code Entry file The entry fil

Miguel

schedule 16 min read

dev_tools

Seven object replication tools, which one do you like best?

In daily programming, we will often encounter scenes of object attribute replication, such as the following common three-tier MVC architecture.   When we program under the above architecture, we usually need to undergo object transformation. For example, after the business request process has gone through the three-tier structure, it needs to be converted from DTO to DO and then stored in the database. When you need to query the data page for display from the data, the query data will be co

Colton

schedule 22 min read

dev_tools

Interviewer: Please use five methods to achieve multi-threaded alternate printing questions

Three threads T1, T2, T3, how to make them execute in order? This is a concurrent programming code question often tested in interviews. Similar questions are: Three threads T1, T2, T3 print ABC in turn, printing n times, such as ABCABCABCABC... Two threads alternately print odd and even numbers from 1-100 N threads cyclically print 1-100 ...... In fact, this kind of problem is essentially a thread communication problem. The idea is basically that one thread finishes execution, blocks the thread,

Hailey

schedule 12 min read

dev_tools

Real-time display of the effect of iOS writing UI code

Article source: www.jianshu.com/p/2ed5f7444... There are roughly two ways to write iOS application UI, one is Storyboard/Xib, and the other is handwritten code. The UI is organized in the Storyboard/Xib way. Due to the visual features, as long as the UI controls are dragged from the UI library, the results can be displayed, which greatly improves the development speed. But one problem is that of multi-person collaborative development. Since all the UI is placed in the same Storyboard file, confl

Gabrielle

schedule 15 min read

dev_tools

The practice of GraphQL and metadata-driven architecture in the back-end BFF

GraphQL is a data query language proposed by Facebook. The core feature is data aggregation and on-demand retrieval. It is currently widely used between the front and back ends to solve the problem of flexible use of data by the client. This article introduces another practice of GraphQL. We will sink GraphQL below the back-end BFF layer and combine metadata technology to achieve on-demand query and execution of data and processing logic. This not only solves the problem of flexible use of data

Adriana

schedule 45 min read

programming

Reproduce the classic: "Statistical Learning Methods" Chapter 10 Hidden Markov Model

This article is a code reproduction of the book "Statistical Learning Methods" [1] by Teacher Li Hang. Author: Huang Haiguang[2] Note: The code can be downloaded in github[3]. I will publish the code one after another on the public account "Machine Learning Beginners", so stay tuned. Code directory Chapter 1 Introduction to Statistical Learning Methods Chapter 2 Perceptron Chapter 3 k Nearest Neighbor Method Chapter 4 Naive Bayes Chapter 5 Decision Tree Chapter 6 Logistic Regression Chapter 7 S

Asher

schedule 9 min read

programming

How to use flask+nginx to build?

Check if the port number is occupied netstat -anp | grep 8080 Click and drag to move and view the process of the application ps aux|grep nginx Click and drag to move the flask part. First, the part of flask writing service is omitted (related to business) The gunicorn part First of all, the way to start our flask project is: app.run(host="0.0.0.0",use_reloader=True, port=5000) Click and drag to move. If we use gunicorn to start, we don t need to write the port number. You can use gunicorn to set

Elijah

schedule 6 min read

programming

vue3 study notes

Introduction to vue3 The official version will be released in September 2020 Compare vue2 vue3 supports most vue2 features Designed a powerful combination API to replace vue2's options API, which is more reusable Better support for TS The main thing: vue3 uses Proxy and Reflect instead of vue2's Object.defineProtory to achieve data responsiveness Rewrite the virtual DOM, faster Designed a new scaffolding tool vite Life hook: beforeDestroy/destroyed in vue3 was renamed to beforeUnmount/unmounted

Aaron

schedule 12 min read

programming

OpenGL_JS-iblCubemap

hdr cubemap export var vs_cubemap = `#version 300 es precision mediump float; layout (location = 0) in vec3 aPos; out vec3 WorldPos; uniform mat4 projection; uniform mat4 view; void main() { WorldPos = aPos; gl_Position = projection * view * vec4(WorldPos, 1.0); }` cubemap ( ) export var fs_equirectangularToCubemap = `#version 300 es precision mediump float; out vec4 FragColor; //out uvec4 uFragColor; in vec3 WorldPos; uniform sampler2D equirectangularMap; // atan(n.z, n.x) UV U // asin(n.y) UV

Daniel

schedule 10 min read

programming

: ( ) ? db ? : +1 : package com.rdpaas.task.scheduler; import com.rdpaas.task.common.*; import com.rdpaas.task.config.EasyJobConfig; import com.rdpaas.task.repository.NodeRepository; import com.rdpaas.task.repository.TaskRepository; import com.rdpaas.task.strategy.Strategy; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import javax.annotation.PostConstruct; import java.util

Benjamin

schedule 10 min read