Programmer Group

A case of blockchain based on PoS consensus algorithmZero. PrefacePreviously, we wrote a case using PoW consensus algorithm, but we found that generating a block using PoW consensus algorithm requires a lot of sha256 encryption operations, which consumes a lot of resources. Our PoS can better solve this problem.1, Define blocks and blockchainst ...

express is a node framework It prepares you for all the back-end needs to do Encapsulate most behaviors into methods (services) An interface location is reserved, and many plug-ins can be registered directly use 1 download using npm install express 2 import using const express = require('express') 3 create service =>After importing, ...

When you need to process Excel files in batches at work, are you still processing them manually one by one? Learn the following automatic batch processing methods and bid farewell to the mechanical and inefficient work!01OS library introductionOS (Operation System) refers to the operating system. In Python, the OS library mainly provides some f ...

01. PrefaceBrush Douban saw the third edition of in-depth understanding of JVM, so he bought it to update the JVM knowledge. This article is a note for personal Review only.02. Java memory area and memory overflow03. Runtime data areaReference: JVM specification, Memories of a Java RuntimeHeap: the memory area created by - Xmx, -Xms when the JV ...

Original link: http://tecdat.cn/?p=24346 1.1 project background:In today's highly homogeneous brand marketing stage, the competition between enterprises is mainly reflected in the competition for customers. "User is God" urges many enterprises to compete for as many customers as possible at any cost. However, in the process of develop ...

Today I want to talk about the problem of circular dependency in spring. Recently, a large number of fans have asked this question, which is often asked in high salary interviews. On the issue of circular dependence, let's feel the serial gun and try whether you can pass the pass and deal with it easily. What is circular dependency? How to ...

Describes how to combine classes or objects to form a larger structure Structural patterns can be divided into class structural patterns and object structural patterns: Class structured pattern: generally, there are only inheritance and implementation relationships. Object structured patterns: according to the "composite Reuse Princi ...

1, Experimental purpose Master the basic MapReduce programming methods through experiments;Master the methods to solve some common data processing problems with MapReduce, including data merging, data De duplication, data sorting and data mining. 2, Experimental platform Operating system: Ubuntu 18.04 (or Ubuntu 16.04)Hadoop version: 3.2.2 ...

Automatic configuration of data sources To access the data source, we need to import the JDBC scenario first <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jdbc</artifactId> </dependency> We found that he did not auto ...

Engineering dependency com.android.dialer is the main project and depends on com.android.contacts.common project and com.android.phone.common project com.android.contacts.common depends on com.android.phone.common project and com.android.common project In addition, some support packages are also introduced as link projects. The above codes ...