#Development

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March 25, 2020Programming
Key-Exchange Logic for Encrypting Interface Data in Front-End/Back-End Separated Projects (RSA, AES)
In front-end/back-end separated projects, sensitive info such as passwords and amounts often needs to be transmitted. Signature/verification algorithms only guarantee data isn't tampered with, but can't keep data confidential. If the user's password is transmitted in plaintext, it can be intercepted by nodes in the network. Although most network operators don't intercept transmitted content, you can't rule out whether the WiFi the user connects to is a phishing network, so sensitive info needs encryption when transmitted. This article discusses how to securely let the client and server exchange keys.
ProgrammingDevelopmentJavaCodeSecurity
March 11, 2020Programming
Encrypt Passwords Properly to Prevent Database Drains and Protect User Login Security
In daily development, passwords are generally just simply MD5'd, and some systems even store users' plaintext passwords directly. If a hacker drains the database and downloads the entire thing, they can log into any account and do dangerous, even irreparable, things. So encrypt passwords properly to protect user account security.
ProgrammingDevelopmentJavaCodeSecurity
March 10, 2020Programming
Tutorial: Actively Pushing Web Pages to Google Search with the Google Indexing API
Google, the world's number one search engine, has long supported webmasters proactively pushing pages, but not through a visual interface for ordinary users — it is done via a programming API. Many webmasters are not professional developers, and because Google requires verifying site ownership, I cannot simply build a visual interface where webmasters enter their own keys. So I wrapped Google's API in a secondary layer to lower the difficulty of using it.
ProgrammingDevelopmentJavaCodeWebsiteOpen Source
March 7, 2020Programming
Can't Tell Object, Generic <T>, and Wildcard <?> Apart in Java? Here's the Clarification
Students who like to study may notice that in other people's code, sometimes Object is returned, and sometimes a <T> generic is used. Code using <T> generics may also contain symbols like <?>. From vague memories of school years ago, you might roughly understand that Object is the parent of all types and can represent any type, and that generics don't restrict the type and can also represent all types — at which point you get confused. Today I'll make their differences clear.
ProgrammingDevelopmentJavaCode
March 5, 2020Programming
GoF's 23 Design Patterns Explained and Demonstrated: (1) Singleton Pattern — Lazy Singleton and Eager Singleton
The Singleton pattern is defined as a pattern where a class has only one instance and the class can create that instance by itself. It is mainly used to solve the frequent creation and destruction of objects, while ensuring logical correctness — for example, only one Task Manager can be opened in Windows, avoiding the waste of memory resources from opening multiple Task Manager windows, or errors such as inconsistent content shown in different windows.
ProgrammingDevelopmentJavaCode
March 4, 2020Programming
GoF's 23 Design Patterns Explained and Demonstrated: Overview
The term "design pattern" did not originally appear in software design, but in architecture. In 1977, the renowned American architect and director of the Center for Environmental Structure at UC Berkeley, Christopher Alexander, described common architectural design problems in his book A Pattern Language: Towns, Buildings, Construction and proposed 253 basic patterns for designing towns, neighborhoods, houses, gardens, and rooms. In 1987, Kent Beck and Ward Cunningham first applied Christopher Alexander's pattern ideas to the generation of graphical user interfaces in Smalltalk, but it did not draw the attention of the software community.
ProgrammingDevelopmentJavaCode
March 3, 2020Programming
Spring Cloud Microservices Beginner Tutorial — Completed
If you have followed me from the first section to create the project and tried running my code (https://github.com/NeilRen/SpringCloudDemo), I believe you can now build a basic microservices architecture. Since this is a beginner tutorial, many things are not covered in depth or detail — the goal was simply to get a microservices architecture up and running. If I have time later, I will try to write an advanced tutorial covering Spring Security, message queues, database distributed master-slave setups, distributed log collection, and so on.
ProgrammingDevelopmentJavaCodeOpen SourceSpring
March 3, 2020Programming
Spring Cloud Microservices Beginner Tutorial (12): Spring Cloud Docker Containerized Deployment
After the previous section on service tracking and link monitoring, the basic microservices framework is nearly complete. Deployment in a microservices setup inevitably involves Docker, so how do we build a Docker image? In this section we'll cover packaging the code into an image file and uploading it to an image repository.
ProgrammingDevelopmentJavaCodeOpen SourceSpringDocker
March 2, 2020Programming
Spring Cloud Microservices Beginner Tutorial (11): Spring Cloud Sleuth + Zipkin Service Tracing and Link Monitoring
In the previous section we covered circuit breaking and degradation, and we can basically build a fairly complete microservices architecture now. But a microservices architecture is distributed — each service runs independently while depending on others — so if a problem occurs, it's hard to trace where it is. We need a service-tracing solution, and Spring Cloud Sleuth provides service tracing and link monitoring.
ProgrammingDevelopmentJavaCodeOpen SourceSpring
March 1, 2020Programming
Spring Cloud Microservices Beginner Tutorial (10): Spring Cloud Hystrix Circuit Breaking and Service Degradation
In the previous section we covered the API gateway, which lets multiple services be published uniformly through the gateway. Before publishing, we also need to understand a mechanism in microservices — circuit breaking and service degradation, called Hystrix in Spring Cloud. This section integrates Hystrix to implement circuit breaking and degradation. Hystrix has many features; we only cover the most commonly used circuit breaking and degradation mechanisms.
ProgrammingDevelopmentJavaCodeOpen SourceSpring