Coder Life - Birost

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Zookeeper Introduction to Introduction (Related Principles, Installation and Startup and Operation)

Pay attention to the WeChat public account: CodingTechWork, learn and make progress together. introduction A summary of the learning and simple use of zk. zk introduction zk overview zk is a high-performance coordination service with high availability. The zk watcher object has two functions: on the one hand, it is used to obtain notifications of zk state changes; on the other hand, it is used to obtain notifications related to znode changes. zk features Zk is simple, and the core is a streamlin

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The difference between Layer 4 and Layer 7 load balancing

kb.cnblogs.com/page/188170... Four-layer load balancing: only establish a TCP connection Seven-layer load balancing: The load balancer establishes a TCP connection with the client and the back-end server respectively. That is, two TCP connections. (One) Simple understanding of four-layer and seven-layer load balancing: The so-called four-layer is load balancing based on IP+port; the seven-layer is load balancing based on application layer information such as URL; similarly, there are two-layer l

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[C++ Advanced] Follow the TDD principle and implement the plane vector class (Vec2D)

table of Contents 1. Clear the methods and member functions of the class to be implemented 2. Assuming that Vec2D has been written, write the test code as required 3. Write the plane vector class Vec2D and test it 4. Complete code 5. The final result 1. Clear the methods and member functions of the class to be implemented Considering efficiency issues, we generally set the parameters of the function to reference types. An important purpose of setting the function parameter type as a reference t

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Get the weather conditions of the city based on the IP address (Java)

The main idea: 1. Obtain the browser's IP address through the request request. 2. Use this IP address to call the external interface to obtain the city name where the IP address is located. 3. After obtaining the city name, call the external interface (weather ) To get the weather information of the city. Calling an external interface: aggregate data Of course, how can we know the city and weather where the IP address is located, we still rely on the interface. (Programming on the shoulders of g

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C++ basic knowledge points

Scattered knowledge points Use cout << a to output a to the command line, and cin >> a to read the input of the command line into the variable a Use #define to define a global constant , which can be directly introduced // Define global constants, it does not belong to any method # define day 7 int main ( int argc, const char * argv[]) { return 0 ; } Copy code Get the occupied content through sizeof(), the unit is byte , and the parameter can be passed variable or type. Such as: size

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Leetcode sliding window summary (1)

table of Contents Summary and code framework 76. Minimum Covering Substring Sliding window Code and comments 567. String arrangement Sliding window 438. Find all letter dysphorisms in the string 3. The longest substring without repeated characters Simplify the framework reference Summary and code framework The sliding window technique is a two-pointer technique. The idea of this algorithm is to maintain a window, keep sliding, and then update the answer. The general framework is as follows: [Re

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About FIN_WAIT1---The state of TCP waved four times

huoding.com/2014/11/06/ A few days ago, a bunch of people chatted in the  TCPCopy  community. Someone asked a question: How long can FIN_WAIT1 last? It sparked a discussion, during which I got enlightenment from Brother Bin and many friends, which benefited a lot. Let's warm up and use an old picture to recall the situation when TCP closes the connection: \ TCP Close As you can see from the picture, the actively closed party sends out a FIN and enters the FIN_WAIT1 state at the same ti

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It's so easy to use! After obtaining offers from three major manufacturers, I found out how powerful the JVM notes given by Xueba are

Hello, today I will share the JVM with you children's shoes, please take out a small book and write it down! Garbage collection scene Cenozoic GC scene In the jvm memory model, the Cenozoic memory is divided into Eden and two Survivors During the continuous operation of the system, the Eden area will be full. Minor GC will be triggered at this time. There is a dedicated garbage collection thread for garbage collection. Different memory areas will have different garbage collectors, which is equiv

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CSS basic finishing

Preface In this article: How to introduce css Commonly used units of css css syntax css style Selector Three characteristics of css Box model float Positioning flex flexible layout Baseline alignment Font icon BFC block-level format context other problems If you have any questions, you can leave a message to me, and I will reply when I see it. If I can't solve it, I can discuss and learn together. If you think there is any mistake, please feel free to give me advice and correct me. Thank you ver

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The long essay tells how I sent Tsinghua University to Tsinghua|The struggle history of underachievers

About the author: Program Yuanshishi (ID: tangleithu), from the 18th-line impoverished rural area ( check my counterattack road ), a BAT factory P7, is the former technical director of DJI (drone), used to be a startup company Have stayed, have a wealth of experience. This article was first published on WeChat official account, the original link , please keep the full text if reprinted. Backstage reply to the keyword "1024" to obtain the interview guide for programmers. background Hello everyon

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4. Cookie WebSQL SessionStorage Redis Redis 4.1 1) SKU 2) Redis Redis 3) changgou_order tb_order_item CREATE TABLE `tb_order_item` ( `id` varchar(20) COLLATE utf8_bin NOT NULL COMMENT 'ID', `category_id1` int(11) DEFAULT NULL COMMENT '1 ', `category_id2` int(11) DEFAULT NULL COMMENT '2 ', `category_id3` int(11) DEFAULT NULL COMMENT '3 ', `spu_id` varchar(20) COLLATE utf8_bin DEFAULT NULL COMMENT 'SPU_ID', `sku_id` bigint(20) NOT NULL COMMENT 'SKU_ID', `order_id` bigint(20) NOT NULL COMMENT ' ID'

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Android uses the SQLite database stored in the assets folder

Article source: blog.csdn.net/trbbadboy/a... Because this project needs to bring its own data, so I put the data in a SQLite database file, and then put the file under the assets folder. At first, I planned to copy the folder from the assets folder to the phone s SD card or the phone s own storage before using it. Later, considering that it s not efficient to copy every time, and if it involves database access The data will be restored after copying if the operation is modified. Therefore, the p

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The role and implementation of distributed locks (Redis, RedisReentrantLock)

blog.csdn.net/l_bestcoder... 1. What is a distributed lock? To introduce distributed locks, we must first mention thread locks and process locks that correspond to distributed locks. Thread lock: Mainly used to lock methods and code blocks. When a method or code uses a lock, only one thread executes the method or code segment at the same time. Thread locks are only effective in the same JVM, because the implementation of thread locks is basically achieved by sharing memory between threads. For e

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Webpack-See the principle of webpack from the implementation of simple packaging

Modularity and webpack In the realization of a simplewebpackBefore we need to understand why we needwebpackWait for the packer to exist. What problems will you encounter when there are no modular tools in the front end? You may need to introduce js into html one by one. There are a few problems with this The introduction of multiple tags means that so many resource requests are a great challenge to performance If the resources have dependencies, you need to ensure the order in which the resource

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Leetcode-The weight of the last stone II

This is the 8th day I participated in the more text challenge. For details of the event, please see the more text challenge Title description There is a pile of stones, with an array of integers stonesSaid. among themstones[i] Represents the first i The weight of a stone. Each round, choose any two stones from them, and then smash them together. Suppose the weight of the stones arex with yAnd x \le y. The possible results of crushing are as follows: in case x == y, Then both stones will be compl

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[Interview Collection] Those pits of String

1. Reference blog Blog address: In- depth understanding of the Java String class 2. Content supplement 2.1 Basic features public final class String implements java . io . Serializable , Comparable < String >, CharSequence { private final char value[]; /** Cache the hash code for the string */ private int hash; // Default to 0 /** use serialVersionUID from JDK 1.0.2 for interoperability */ private static final long serialVersionUID = -6849794470754667710L ; ... } Copy code From part of the

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Take you to make a cute sliding navigation bar in 5 minutes!

This is the fourteenth day of my participation in the Wenwen Challenge. For details of the event, please view: Wenwen Challenge Hey there! Hello everyone, today I will take you to make a cute sliding navigation bar effect. This demo is very basic, but the usage scenarios are very wide! As a front-end master, I will teach you step by step to implement it today! Achieve effect Look! This sliding effect is very interesting! I believe you must have thought about this sliding effect! Implementation p

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Summary of reflection knowledge review

Why use reflection mechanism? Since java objects can passnewKeyword creation, so why introduce reflection?newThe premise of using the keyword is that you must know the name of the class. If you don't know the name of the class at this time, then you cannot achieve the creation of the class by hard coding. At this time reflection plays a big role.The purpose of reflection is to expand unknown applications Simple use review The realization of the reflection mechanism is mainly dominated by three c

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"Study Notes" 001-SpringWeb

SpringWeb Java Servlet is a program running on a Web server or application server. It acts as an intermediate layer between a request from a Web browser or other HTTP client and a database or application on the HTTP server. HTTP protocol Hyper Text Transfer Protocol Features: HTTP is connectionless : the meaning of connectionless is to limit each connection to only process one request. After the server has processed the client's request and received the client's response, it will disconnect. In

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Python 3.6 study notes (1)

Knowledge is a treasure house, and practice is the key to open this treasure house. ----Thomas Fuller before the start Basic example Python grammar is basic, python grammar is relatively simple, and adopts the condensing method. Absolute value of A Print # Integer A = 100 IF A> = 0 : Print (A) the else : Print (-a) copying the code As you can see, comments start with # , Python variables do not need any prefixes, and line ends do not need end symbols, which is very consistent with our natura

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