This article explains the concept of idempotent HTTP requests, defines idempotency, lists which HTTP methods are idempotent or not, and clarifies why methods like GET, HEAD, PUT, DELETE are safe to retry while POST, PATCH, and CONNECT are not.
This article explains how to overcome performance bottlenecks of a rapidly growing blog by progressively enhancing the traditional Nginx‑MySQL stack with load‑balanced app servers, Redis caching, read/write splitting, MySQL partitioning, MyRocks, and finally a hybrid NoSQL‑big‑data architecture using Hadoop and HBase.
This article explains why a server must invoke listen() after bind(), detailing the kernel's listen system call, how it creates and initializes the full‑connection and half‑connection queues, and how their lengths are calculated based on backlog, somaxconn, and tcp_max_syn_backlog parameters.
This article provides a thorough overview of backend development, covering system development principles, architectural design patterns, network communication techniques, common faults and exceptions, monitoring and alerting strategies, service governance practices, and deployment workflows, all illustrated with clear explanations and practical examples.
This article explains the behavior of NaN values in Go maps, demonstrates a related IEEE‑754 quiz, and discusses the ongoing proposal to introduce a delete(m) function that can reliably clear maps even when they contain NaN keys.
This article details how JD's retail shopping‑cart team tackled growing business complexity by fully converting the cart service to an asynchronous architecture, addressing challenges such as increasing RPC dependencies, pagination, and resource costs, and achieving a 30% reduction in core interface latency.
The article explains how to select and implement routing keys for database sharding in an order platform, covering time‑based and business‑related keys, user and merchant scenarios, hash‑modulo strategies for single and multi‑database environments, and the overall data flow.
The article explains why calling PHP's session_start() multiple times generates duplicate Set-Cookie headers, provides a code-based fix using session_abort() and header_remove(), and discusses session file locking, cookie lifetime, and garbage collection settings to manage session behavior effectively.
This article details a systematic approach to reducing image sizes for ISV‑generated pages, covering offline compression, WebP conversion, data structure design, batch processing pipelines, monitoring, and fallback strategies, while providing code examples and performance comparisons.
This article provides a comprehensive overview of process engines, explaining their definition, relationship to workflows and BPM, design of process designers, various application scenarios such as workflow and BPM, detailed architectural components, implementation practices, and potential business opportunities, illustrated with diagrams and XML examples.
This article explains common cache update patterns—Cache Aside, Read‑Through, Write‑Through, and Write‑Behind—illustrates their read/write flows, highlights typical pitfalls such as dirty data caused by wrong update order, and offers practical safeguards for maintaining data consistency in large‑scale systems.
This guide walks you through installing the MyBatisCodeHelper‑Pro IntelliJ plugin, configuring it to generate Java entity, DAO, mapper and service code, customizing type mappings, creating SQL scripts, and using shortcuts to produce find, update, delete, and pagination methods efficiently for backend development.
This article provides a detailed tutorial on Spring Security, covering its core concepts, project setup, authentication flow, custom user details service, password encoding, login handling, role-based access control, CSRF protection, and integration with Thymeleaf, complete with code examples.
The article explains why front‑end and back‑end should be separated, outlines the challenges of integration, describes the responsibilities and development process for a clean API contract, and provides detailed request/response specifications with code examples for building a maintainable SPA architecture.
This article explains how to size Redis memory, configure maxmemory and maxmemory‑policy settings, and choose among various eviction strategies—including no‑eviction, allkeys‑lru, allkeys‑lfu, and volatile options—while detailing the underlying LRU and LFU algorithms used by Redis.
The article discusses the importance of clear application layering, outlines Alibaba’s multi‑layer architecture, proposes an optimized layering model, explains domain object types (DO, DTO, BO, AO, VO, Query) and offers practical guidelines to improve code maintainability and reuse in backend development.
This article examines how adopting software frameworks—especially web frameworks—can undermine long‑term maintainability through control inversion, mismatched goals, design trade‑offs, and hidden costs, while also showing how a decoupled approach can retain benefits without the drawbacks.
The article evaluates common approaches for implementing delayed tasks such as order‑closing, critiques unreliable methods like Redis expiration listeners and RabbitMQ dead‑letter queues, and recommends robust solutions like RocketMQ, Pulsar, or Redisson delay queues with proper compensation mechanisms.
This article walks through the complete design and implementation of a high‑performance user login system, covering client‑side verification, server‑side token generation, token expiration strategies, gateway authentication, logout handling, anonymous request allowances, rate‑limited auth tokens, and blacklist management, illustrated with diagrams and Java Spring code examples.
The article examines three approaches to handling inventory deduction in e‑commerce—single‑field MySQL, sharded MySQL rows, and Redis incrby—analyzes their concurrency drawbacks, and presents a robust Redis‑Lua script solution with distributed locking and Java implementation details.
This article explains Netty's high‑performance asynchronous architecture, compares classic multithread, Reactor, select, poll and epoll I/O multiplexing models, describes level‑triggered versus edge‑triggered event handling, and provides a step‑by‑step JNI example and a hand‑written epoll server implementation in C.
This guide walks through setting up a Python 3.8 environment, configuring SQL Server authentication, installing pymssql and ttkbootstrap, and running a Tkinter‑based application via command line or Visual Studio, complete with screenshots and a QR code for additional Python learning resources.
This article explains the differences between short and long connections, why long‑connection services need load balancing, and presents practical strategies for connection‑level balancing, handling server restarts, heterogeneous hardware, and scaling challenges.
This article explains the fundamentals of in‑memory caching, introduces Guava's LoadingCache API, discusses cache sizing, eviction policies, common algorithms like FIFO, LRU, LFU, shows a simple LRU implementation using LinkedHashMap, and provides practical guidance on when and how to apply caching for performance optimization.
This article provides a comprehensive overview of Dubbo, a high‑performance Java RPC framework, detailing its three core capabilities, essential components, layered architecture design, and the step‑by‑step remote invocation workflow for both service providers and consumers.
This article provides an in‑depth overview of microservice architecture, covering its definition, history, differences from monolithic and SOA approaches, core characteristics, design patterns, advantages and drawbacks, practical deployment considerations, and recommended reading resources.
This article explores the fundamentals of data saving for web‑based tools, covering what data is saved, where it is stored (backend vs. frontend), various trigger mechanisms, design principles for reliable saving, and feedback patterns to ensure users never lose their work.
This article explains how Netty implements a powerful asynchronous, event‑driven architecture using the Reactor pattern, compares classic multithread, select, poll and epoll I/O multiplexing models, demonstrates JNI integration with Java, and provides a complete, annotated epoll server example with level‑triggered and edge‑triggered handling for high‑concurrency backend development.
This article examines how the mic‑queue list in a live‑streaming app caused heavy server load due to three‑second polling, and details a systematic performance‑optimization process—including analysis, reducing I/O, employing Go’s singleflight caching, and switching JSON libraries—to cut resource usage by up to 60% while preserving user experience.
This article examines common misconceptions about application layering, outlines Alibaba's multi‑layer architecture—including Open Interface, Terminal Display, Web, Service, Manager, and DAO layers—offers optimized layering practices, explains domain model transformations, and provides actionable guidelines for building maintainable, reusable backend systems.
Node.js 19, released today, updates the V8 engine to version 10.7, enables experimental node --watch mode, defaults HTTP/1.1 Keep‑Alive, stabilizes the WebCrypto API, removes experimental specifier‑resolution flag, and deprecates DTrace/SystemTap/ETW support while bundling llhttp 8.1.0 and npm 8.19.2.
This article explains how to use Java's java.util.concurrent.Semaphore together with a fixed-size thread pool to enforce a precise QPS limit for asynchronous tasks, providing API details, implementation steps, and a complete test example.
This article explains the browser same‑origin policy, defines cross‑origin requests, outlines the restrictions they impose, and presents five practical ways—global filter, WebMvcConfigurer, @CrossOrigin annotation, manual response headers, and a custom filter—to enable CORS in a Java Spring MVC backend with complete code examples.
This comprehensive guide explains how to configure Nginx as an HTTP server, static file server, reverse proxy, and load balancer, covering directory setup, location matching rules, priority order, upstream strategies, and useful directives such as return, rewrite, error_page, logging and access control.
This article provides a comprehensive overview of various load balancing strategies—including round‑robin, random, weighted, smooth weighted round‑robin, consistent hashing, least‑active, and optimal‑response algorithms—explaining their principles, advantages, disadvantages, use‑cases, and offering complete Java code examples for each.
The author recounts his 2023 autumn recruitment experience, detailing his background, internships, extensive job applications, interview outcomes, study strategies covering fundamentals, design patterns, and distributed systems, and offers practical advice for fellow graduates navigating the competitive tech job market.
The article explains how microservice architectures can achieve high availability by isolating failures, employing graceful degradation, change‑management strategies, health checks, fallback caching, retry logic, rate limiting, circuit breakers, and chaos testing, while acknowledging the added complexity and cost of such reliability engineering.
This article explains what ULID is, why it can be a better alternative to UUID, outlines its key characteristics and specification, and provides practical Python examples for generating and handling ULIDs in distributed backend systems.
The article builds five microservices with Helidon SE, Ktor, Micronaut, Quarkus and Spring Boot, integrates Consul for service discovery, provides full source code and configuration, shows how to start each service, benchmarks size, startup time and memory usage, and finally lists the pros and cons of each framework.
This article walks through the evolution of a simple online supermarket from a monolithic website to a fully split microservice architecture, highlighting the challenges encountered—such as code duplication, database bottlenecks, and operational complexity—and presenting practical solutions like service decomposition, monitoring, tracing, gateway control, service discovery, circuit breaking, rate limiting, testing strategies, and the use of service meshes.
This tutorial walks through multiple Python approaches for downloading files—including simple requests.get calls, the wget module, handling redirects, chunked large‑file downloads, parallel batch downloads, proxy usage with urllib, S3 retrieval via Boto3, and asynchronous fetching with asyncio—providing code examples and best‑practice tips.
This guide explains how to upgrade to Alipay’s new transfer interface, alipay.fund.trans.uni.transfer, by updating the SDK, configuring certificates, adding Maven dependencies, and implementing Java Spring beans and utility classes for secure fund transfers.
Spring 6 introduces major updates such as moving JSR‑330 and JSR‑250 annotations to Jakarta packages, deprecating ListenableFuture, requiring Hibernate 5.6.x with jakarta.persistence, updating servlet containers, altering controller detection, converting HttpMethod to a class, and adjusting Kotlin and RestTemplate APIs.
This article presents thirteen practical guidelines for optimizing Redis performance, covering command selection, key management, data structures, persistence settings, hardware choices, clustering, and memory fragmentation mitigation to achieve significant speed improvements.
This article explains how to select and implement routing keys for database sharding in a food‑delivery order system, covering supported scenarios, single‑ and multi‑database strategies, hash‑based distribution for both user and merchant data, and practical flow diagrams to ensure balanced and efficient data access.
This article examines the open‑source memory cache Dragonfly, compares its performance and architecture with Redis through detailed benchmark reproductions, discusses the underlying design trade‑offs, and highlights Redis’s continued relevance and future directions in real‑world deployments.
This article walks through MyBatis's complete query lifecycle—from configuration parsing, SqlSessionFactory creation, and mapper loading to the actual SELECT execution—while reproducing a pre‑3.4.5 bug caused by foreach variable leakage and presenting the official fix and upgrade recommendations.
This guide explains Nginx load balancing concepts, compares hardware and software approaches, details various balancing algorithms with configuration examples, and shows how to integrate Nginx with SpringBoot for practical load‑balancing tests and deployment tips.
After moving to a new team lacking a dedicated gateway, the author evaluates two popular microservice gateway solutions—Spring Cloud Gateway and Apache APISIX—comparing their features, cloud‑native capabilities, performance, and ease of use, ultimately selecting Spring Cloud Gateway for its Java ecosystem and extensibility.
This article demonstrates how to create a perpetual multithreaded Java task using a custom thread‑pool utility, supports concurrent execution of multiple long‑running jobs, and implements an elegant shutdown that drains remaining work before terminating.
Onion Architecture, a DDD‑aligned design pattern, structures applications into concentric layers centered on the domain model, promoting loose coupling, testability, and technology‑agnostic core logic, while detailing principles, layer responsibilities, testing strategies, microservice applicability, modular packaging, and practical implementation considerations.
The article explains the core performance metrics QPS, TPS, response time (RT), concurrency, and throughput, provides formulas to relate them, demonstrates practical calculations for capacity planning, and discusses how to determine the optimal number of threads for a backend system.
This article provides a comprehensive guide to upgrading Spring Boot to version 2.7, detailing common issues such as missing dependencies, logging conflicts, circular bean references, Swagger configuration changes, Flyway compatibility, JUnit version mismatches, and JSON Long precision loss, along with concrete code‑based solutions.
This article explains how to replace bulky if‑else chains in Java with a lightweight strategy‑enum approach, improving readability, extensibility, and reducing procedural code by leveraging enum‑based strategy pattern for daily task scheduling.
Explore the 11 most commonly used Spring extension points—from custom interceptors and bean factories to global exception handling, type converters, import mechanisms, startup runners, bean lifecycle processors, and custom scopes—complete with clear code examples and practical guidance for enhancing Java backend applications.
This article compares JWT and session authentication, explains their differences, outlines the authentication flows, evaluates advantages, disadvantages, security, performance and one‑time use issues, and provides a complete Java implementation with JWT, Redis, interceptor and utility classes.
Pyston 2.3.5, a fork of CPython 3.8 maintained by Anaconda, delivers double‑digit performance gains for network‑service workloads, offers two‑fold speedups on micro‑benchmarks like chaos.py and nbody.py, and remains highly compatible with the full CPython feature set and C API.
This article explains how Nginx can be used to achieve various load‑balancing strategies—including round‑robin, least connections, IP hash, generic hash, random and least‑time—provides concrete upstream and server configuration examples, shows how to integrate Nginx with a Spring Boot application, and details testing procedures to verify balanced request distribution.
This article discusses the importance of proper backend application layering, outlines Alibaba's multi‑layer architecture (controller, service, manager, DAO, etc.), explains domain model transformations (DO, DTO, BO, VO, etc.), and offers practical recommendations for achieving clear responsibilities and maintainable code.
The article explains why clear application layering—covering controller, service, manager, and DAO levels—is essential for maintainable backend code, describes Alibaba's recommended layer structure, proposes an optimized layering model, and outlines domain object conventions such as DO, DTO, BO, AO, VO, and Query.
This article introduces RobustDB, a client‑side read‑write splitting framework that replaces the problematic Atlas proxy by routing SQL statements to master or slave databases based on DML/DQL detection, using Spring, AspectJ, thread‑local context, and dynamic data‑source management.
This article explains how to build a highly extensible, modular backend service using Spring Cloud, demonstrates practical module composition and separation, discusses RESTful API design principles, presents concrete Java code examples for commands, controllers and pagination, and reviews popular API documentation tools such as Swagger, SpringDoc and Knife4j.
This article explains why well‑designed APIs are essential, covering data modeling, resource hierarchy, naming conventions, RESTful principles, CRUD operations, versioning strategies, and pagination techniques, and provides concrete examples and guidelines to help developers create robust, maintainable, and developer‑friendly APIs.
This article explains the causes of duplicate message consumption in RabbitMQ, demonstrates how to reproduce the issue with a 10,000‑message test, and provides three practical solutions using unique IDs stored in Redis to ensure idempotent processing in Java Spring applications.
This article explains the compatibility challenges between Java functional interfaces and Groovy closures, introduces a utility class that converts Supplier, Function, Predicate, and Consumer into Groovy closures, and provides a complete code example with demonstration and output.
This article explains how to set up remote debugging for services in sandbox or test environments, covering remote creation, locating debug ports, constructing JVM arguments, checking service status, stopping services, and useful alias commands to streamline the debugging process.
This article compiles a large set of interview questions frequently asked by top tech companies, covering Java fundamentals, multithreading, Spring framework, MyBatis, Redis, and related concepts, and provides a free QR‑code link for downloading the complete question set with answers.
This article explains why PHP 7.0's json_decode throws JSON_ERROR_UTF16 when encountering malformed Unicode surrogate pairs, demonstrates the problem with example code, and details the underlying re2c scanner logic that causes the error, offering insight for backend developers.
The article dissects Node.js v17’s source to reveal how the CommonJS `require` system is bootstrapped, how native modules are loaded, how `Module._load` resolves, caches, and executes user files, and how the overall CJS loading pipeline operates step‑by‑step.
The article explains why interviewers probe the implementation details of backend components such as Redis, HashMap, and Memcached, illustrates common interview questions, and shows how mastering the underlying data structures, algorithms, and memory‑allocation mechanisms can improve both interview performance and real‑world problem solving.
This article explains how to leverage Spring Application Events to decouple business logic, demonstrates creating custom events, listeners, and publishers, shows both synchronous and asynchronous handling with @EventListener and @Async, and provides complete code samples and test results.
This article explains the requirements for a Redis‑based distributed lock, analyzes Redisson's watchdog lock implementation—including tryLock and unlock flows, Lua atomic scripts, single‑instance versus cluster limitations—and provides practical tips to avoid common pitfalls in production environments.
This article explains the fundamentals of Java thread pools, covering their purpose, construction parameters, execution process, worker reuse, task retrieval with timeout, lifecycle states, shutdown methods, monitoring techniques, and practical guidelines for customizing thread pools in real-world projects.
This article explains why and how to separate frontend and backend responsibilities, outlines the evolution from MVC to SPA architectures, and provides detailed API request and response conventions—including JSON formats, pagination, and special field handling—to improve collaboration and reduce integration effort.
The article outlines a practical backend design for handling 20 million daily ID lookups across a billion records, showing how modest hardware—20 virtual machines with 16 GB RAM each—can meet the load using simple sharding, in‑memory storage, and basic networking techniques.
This article explains three Java request‑collapsing approaches—Hystrix Collapser, a custom BatchCollapser, and Guava's ConcurrentHashMultiset—detailing their implementations, configurations, and ideal usage scenarios to reduce downstream load and improve system throughput.
This article explains the Java Service Provider Interface (SPI) mechanism, its core principles of decoupling and dynamic loading, walks through the ServiceLoader source code, and demonstrates how to apply SPI in both web and Android projects with Gradle configurations and sample modules.
This article provides a comprehensive guide to implementing and testing Go Redis Set APIs—including SAdd, SCard, SIsMember, SMembers, SRem, SPop, and SPopN—complete with code examples, a unified test suite, and a performance benchmark that reports QPS and execution time.
The article explains how to prevent duplicate write requests on the server by using unique request IDs with Redis, computing MD5 digests of business parameters (excluding volatile fields like timestamps), and provides a reusable Java helper class with example code and test logs.
This guide explains how to name REST API resources using nouns, plural forms, hyphens, and versioning while avoiding verbs, underscores, trailing slashes, and file extensions, and shows how to apply query parameters and standard CRUD operations for clean, intuitive URIs.
This article explains the principles, implementation steps, and configuration of MyBatis first‑level (SqlSession) and second‑level (mapper) caches, compares their scopes and behaviors, and provides practical guidance on when and how to enable each cache to improve database query performance.
This article explains the background, simple single‑table and complex sharding designs, global versus store‑unique strategies, and practical solutions such as distributed locking and retry mechanisms for generating and managing pickup codes in a SaaS e‑commerce system.
This article explains the IDEA warning for @Autowired field injection, compares @Autowired and @Resource, outlines the pros and cons of constructor, setter, and field injection in Spring, and clarifies why only @Autowired triggers the warning due to its tighter framework coupling.
This article explains the five SOLID object‑oriented design principles—Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion—while also promoting a PHP online training program that covers modern web technologies and offers enrollment via QR code or contact details.
The article explains why front‑back end separation is needed, describes the evolution from MVC to SPA, outlines responsibility separation, development workflow, and presents a detailed API specification including request/response formats, pagination, and special data handling rules.
This article explains why Spring singleton beans can be unsafe in concurrent scenarios, demonstrates the issue with a controller example, and presents multiple solutions including changing bean scope, using ThreadLocal, avoiding member variables, employing concurrent collections, and leveraging distributed caches.
This article details how the Sohu video PUGC team refactored a legacy video‑object‑creation API by introducing a reactive, asynchronous, non‑blocking architecture built on RxJava, Vert.x WebClient and a custom Dubbo reactive client, achieving clearer business flow and a 43% latency reduction.
Discover fourteen actionable Spring Boot optimization techniques—from using @ConfigurationProperties and @RequiredArgsConstructor to modularizing code, avoiding null returns, leveraging IDE shortcuts, and applying design patterns—each illustrated with examples to help Java developers write cleaner, more maintainable, high‑performance applications.
This article traces the evolution of internet architecture from monolithic to distributed and microservice models, explains the concepts of serviceization and service governance, and details how Dubbo implements these ideas while highlighting the benefits, challenges, and practical implementation steps for modern backend systems.
The article outlines a simple, cost‑effective backend architecture for handling up to 20 million daily health‑status queries across a billion users, detailing data storage, sharding by ID, memory requirements, load handling, and redundancy strategies, while noting practical limitations and promotional notes.
This article explains the core concepts of low‑code platforms, emphasizing visual editing as a mandatory feature, comparing declarative and imperative approaches, detailing front‑end JSON‑to‑React rendering, reviewing five back‑end storage strategies, discussing business‑logic implementation, workflow engines, and predicting the future evolution of low‑code solutions.
This article describes how Baidu's commercial frontend team improved front‑end and back‑end collaboration efficiency by introducing a BFF layer, data‑direct capabilities, staged data tiering, and fragment‑based batch editing, ultimately reducing delivery time by over 50% while maintaining quality.
Cube.js is an open‑source, headless business intelligence platform that provides fast, scalable analytics via REST, SQL, and GraphQL APIs; the article explains its key features, why to choose it, Docker‑based deployment steps, and integration options with various front‑end visualization tools.
This article uses a simulated Taobao example to illustrate how a simple MVP monolithic architecture evolves through ten stages—from separating Tomcat and database to adopting caching, load balancing, database sharding, microservices, ESB, containerization, and cloud platforms—highlighting the technologies and design principles involved in each transition.
This article describes the design, hardware and software setup, implementation, testing phases, and performance analysis of a Go‑based backend system that simulates a Spring Festival red‑envelope service capable of handling up to 10 billion requests with peak loads of 60 k QPS per server.
This article explains how Spring Boot’s auto‑configuration works, covering the role of application properties, the @EnableAutoConfiguration annotation, condition annotations, the spring.factories mechanism, and how configuration properties are bound to beans such as ServerProperties to make settings like server.port effective.
The article details how a gaming data‑reporting pipeline uses Redis lists, sets and Lua scripts to build a pseudo‑message queue that provides per‑game message grouping, fixed‑length queues, and batch consumption while meeting strict timeliness and throughput requirements.
This article describes a systematic model that enumerates all possible city‑county home page switching scenarios in the 58App, identifies conflicting popup configurations, and proposes a concise feature‑flag protocol to eliminate popup conflicts while reducing client‑side logic and operational overhead.
The article explains why e‑commerce users sometimes see their payments completed in the wallet but the order remains unpaid, analyzes internal and external drop‑order scenarios, and provides practical server‑side, client‑side, and active‑query techniques—including scheduled tasks and delayed‑message queues—to prevent such issues.
This article explains Tomcat's component architecture, describes the request‑processing flow, and provides practical guidance on tuning the three critical parameters—maxThreads, maxConnections, and acceptCount—along with additional settings to improve backend service performance without additional hardware.
