This article explains the difference between FastJSON's getInteger and getIntValue methods, analyzes a common validation bug in a custom isRight() implementation, and provides corrected code examples and optional global switches for robust response handling in Java backend projects.
This article outlines a variety of practical Redis use cases—including caching, distributed sessions, locks, global IDs, counters, rate limiting, bitmap statistics, shopping carts, timelines, message queues, lotteries, likes, product tagging, filtering, follow/recommendation models, and ranking—demonstrating how Redis can support diverse backend functionalities.
The PHP imagecolormatch function adjusts the colors of a palette‑based image to better align with a true‑color image by taking two image resources of identical dimensions, returning TRUE on success or FALSE on failure, and is demonstrated with a complete example script.
This article presents a collection of practical PHP utility functions—including string truncation with ellipsis, MD5-based encryption, phone number masking, mobile, numeric and email validation, as well as recursive category handling—complete with usage scenarios and full source code to help developers quickly implement common backend tasks.
The article explains how Xianyu’s search service refactors tightly‑coupled, if‑else‑heavy code by applying the lightweight SWAK framework—defining @SwakInterface and @SwakTag annotations, registering proxy beans, using AOP and CGLIB proxies to route business logic via request‑derived tag groups, achieving clean, modular routing.
This article introduces WebSocket, explains why it is preferred over HTTP for real‑time communication, and provides a complete Spring Boot integration tutorial with Maven dependencies, configuration, server endpoint code, controller, and a simple HTML client, all illustrated with runnable examples.
To prevent duplicate OpenID records caused by concurrent synchronization requests in the Fast App Center, this article analyzes the root cause, evaluates database‑level unique indexes versus application‑level distributed locks, and presents a Redis‑based lock implementation with cleanup procedures to ensure data consistency.
The article explains the concepts, rules, and evolution of layered architecture—including strict layering, relaxed layering, and inheritance‑based layering—while illustrating practical implementations with Java code and discussing how front‑end separation and DDD influence architectural decisions.
The article explains PHP's imagecolorat function, which returns the RGB integer of a pixel in a true‑color image using the GD library, and shows how to extract red, green, and blue components with bitwise operations through a complete code example.
This article explains the four rejection policies of Java's ThreadPoolExecutor, shows the default AbortPolicy behavior, provides code examples for each policy, and demonstrates how to configure custom policies using both raw ThreadPoolExecutor and Spring's ThreadPoolTaskExecutor.
This article explains how to achieve dynamic creation, removal, activation, and deactivation of scheduled tasks in a Spring Boot application by customizing the ScheduledTaskRegistrar and related components, providing a lightweight alternative to integrating the Quartz framework.
This article explains how the PHP GD function imagecolorallocatealpha() assigns colors with transparency to an image, describes its parameters and return values, and provides a complete example that creates a PNG with overlapping circles using custom alpha values.
This article examines how Baidu Search achieves five‑nine‑plus availability by analyzing stability challenges, introducing the Kepler 1.0 observability stack, evolving to Kepler 2.0 with full‑trace collection, custom compression, and practical use‑cases that dramatically improve fault diagnosis and capacity management in a massive micro‑service environment.
The article explains PHP's imagecolormatch function, detailing its purpose of aligning palette colors with true‑color images, outlines required parameters, return values, and provides a complete PHP example using GD library functions to demonstrate usage and cleanup.
PHP 8.0.9 has been released as a bug‑fix version, encouraging all PHP 8.0 users to upgrade, and it includes numerous core, Intl, OpenSSL, PCRE, Reflection, and Standard component fixes detailed in the official changelog.
The article explains how intermittent latency spikes (jitter) in a high‑throughput service can be triggered when the JVM’s Just‑In‑Time compiler activates, detailing interpreter vs. JIT, C1/C2 tiered compilation, hot‑spot detection thresholds and compilation stages, and recommends pre‑warming code, disabling tiered compilation, or tuning thresholds and JVM flags to eliminate jitter.
This article explains the different blocking queue implementations—ArrayBlockingQueue, LinkedBlockingQueue, SynchronousQueue, and PriorityBlockingQueue—used by Java thread pools, describing their structures, behavior, fairness settings, and performance characteristics for concurrent task execution.
This article explains the concept of microservices, compares them with traditional monolithic web applications, outlines their advantages and challenges, and introduces first‑generation frameworks like Spring Cloud and Dubbo as well as next‑generation service‑mesh solutions such as Linkerd, Envoy, Istio, and Conduit, especially in Kubernetes environments.
This article details how to optimize a high‑traffic weekly report service by adding composite indexes, partitioning data into weekly tables, leveraging Redis caching, and employing data pre‑warming to dramatically reduce query latency and database load.
The article defines strong versus weak service dependencies, outlines governance through discovery, fault injection, and refactoring, recommends front‑end and back‑end fault‑tolerance measures such as timeouts and circuit breakers, describes isolation and artificial degradation switches, verifies classifications, and notes current middleware gaps and hiring information.
This page aggregates over 300 curated interview question articles covering Java backend development topics such as Spring, MySQL, Redis, concurrency, data structures, and system design, organized by issue numbers to help candidates prepare effectively for technical interviews.
The PHP function imagecolorallocate() assigns a color to an image resource by specifying red, green, and blue components (0‑255 or hexadecimal), returns a color identifier or -1 on failure, and is demonstrated with example code showing how to set background, white, and black colors.
The article outlines a complete e‑commerce payment architecture, detailing the transaction core and the extensive payment orchestration layer, and provides numerous diagrams that illustrate how each component interacts to achieve scalable, reliable, and secure online payment processing.
The article explains the PHP imagechar function, detailing its parameters, return values, and usage, and provides a complete example that creates an image, allocates colors, draws a character, sets the header, and outputs the PNG image.
This article provides a comprehensive Python tutorial covering how to send GET and POST requests, handle HTTPS verification, perform file uploads and downloads, set request timeouts, use basic and token authentication, manage sessions, generate signatures, and organize a test automation framework with configuration, common utilities, test data, test cases, reporting, and execution scripts.
This article provides a comprehensive overview of message middleware concepts, the role and benefits of message queues, and an in‑depth look at RabbitMQ architecture, components, reliability mechanisms, advanced features, and internal storage and flow‑control mechanisms.
This article introduces wx‑manage, an open‑source WeChat public‑account management system that supports multiple accounts, offering menu, auto‑reply, material management, and a simple CMS, and details its Spring Boot‑based tech stack, required environment, and where to obtain the source code.
The release of MyBatis‑Mate 1.0.1 introduces enterprise‑grade features such as dictionary binding, field encryption, data desensitization, automatic DDL maintenance, and dynamic multi‑datasource sharding, accompanied by code examples, future roadmap, and Maven dependencies for seamless integration into Spring Boot projects.
The PHP imagearc() function draws an elliptical arc on a GD image resource using specified center coordinates, width, height, start and end angles, and color, returning the transformed image on success or FALSE on failure, with a full example demonstrating its usage.
This article explains the circuit breaker pattern, its three-state lifecycle, and provides a detailed Go implementation with code examples, state transition logic, metric tracking, and known limitations for improving service stability.
This article explains how to identify and resolve Redis slow queries by using the slow query log, understanding command complexity, replacing inefficient commands with more efficient alternatives, and configuring slowlog parameters for optimal performance.
This article explains the theory behind TCC distributed transactions, describes its three-phase workflow and roles, and provides a complete Python implementation using the DTM framework, including deployment steps, code examples, and handling of both successful commits and rollbacks.
This article explains Java's reflection mechanism, discusses its strengths and weaknesses, and demonstrates common scenarios such as JDBC connection setup and Spring framework bean loading with clear code examples, helping developers decide when to apply reflection in backend development.
This step‑by‑step guide shows how to set up the Sentinel dashboard, add the Sentinel client to a Spring Boot project, define protected resources programmatically or with annotations, start the dashboard, and configure flow‑control and degradation rules to limit API traffic.
This article presents a comprehensive visual overview of microservice concepts and architecture evolution, detailing the transition from monolithic to SOA and microservice styles, and introduces Spring Cloud’s core components—including Eureka, Ribbon, Feign, Hystrix, Zuul, Gateway, Config, Bus, OAuth2, and Sleuth—illustrated with 19 mind‑map diagrams.
Over a month of systematic JVM tuning reduced Full GC from 40 times per day to once every ten days and halved Young GC duration by adjusting heap sizes, survivor ratios, and metaspace settings while investigating and fixing a memory leak caused by an anonymous inner class listener.
This article outlines a complete backend technology stack for startups, covering language choices, core components, processes, systemization, and detailed selections for project management, DNS, load balancing, CDN, RPC frameworks, service discovery, databases, messaging, logging, monitoring, configuration, deployment, and operational best practices.
This article traces the historical development of microservice architecture from monolithic to distributed services, outlines its advantages and drawbacks, and presents a comprehensive technology stack—including service communication, API gateways, authentication, fault tolerance, logging, configuration, containerization, orchestration, and CI/CD—to guide practitioners in building robust, scalable backend systems.
The article explains the role of an API Gateway as the single entry point for a system, detailing its core modules such as routing, service registration, load balancing, resilience, security, gray‑release, API aggregation and orchestration, and outlines key design, operational, and architectural considerations for building a high‑performance, highly available, and extensible gateway.
This guide outlines a comprehensive backend technology stack for startups, covering language choices, core components, development processes, infrastructure services, database options, monitoring, CI/CD, and operational best practices to help teams design, select, and implement a reliable server-side architecture.
This article explains Aspect‑Oriented Programming (AOP) in Spring Boot, covering its core concepts, why it simplifies cross‑cutting concerns like logging and permission checks, provides step‑by‑step code examples of simple and advanced AOP implementations, and details the most commonly used AOP annotations.
This article explains why rate limiting is essential for high‑availability services, describes HTTP 429 standards and response headers, classifies rate‑limiting strategies by granularity, target, and algorithm, and provides detailed Go code examples using the time/rate library for fixed‑window, sliding‑window, leaky‑bucket, and token‑bucket implementations.
The article explains the concepts of cache penetration, cache breakdown, and cache avalanche in Redis‑based systems, describes the performance risks they pose to persistent databases, and presents practical mitigation techniques such as Bloom filters, empty‑object caching, hot‑key permanence, distributed locks, high‑availability clusters, rate limiting, and data pre‑warming.
This article explains why global exception handling is needed in Spring MVC, outlines its application scenarios, compares AOP with the simpler @ControllerAdvice/@ExceptionHandler approach, and provides detailed code examples for custom response objects, validation handling, and transaction rollback strategies to improve code cleanliness and maintainability.
The article narrates the progressive design of a customizable workflow engine, starting from a simple linked‑list approver chain and evolving through countersign, parallel, conditional, delegation, timeout, progress‑percentage, and script‑hook features, illustrating each stage with node classifications, state definitions, and tree‑based structures.
This tutorial explains why RESTful API versioning is needed, presents four versioning strategies (URI, request parameter, custom header, and media type), provides Spring Boot code examples for each, and discusses factors to consider when choosing a versioning approach.
The article explains PHP's image2wbmp() function, detailing its parameters ($image, optional $filename, optional $threshold), return value, and how to output a WBMP image directly or save it to a file, and includes a complete code example.
The article traces the evolution of backend services from monolithic applications through RPC-based scaling and sharding, highlights the limitations of database connection counts, and proposes a unitized architecture that partitions databases per service to achieve true unlimited scaling while acknowledging added complexity.
This article examines how Nacos leverages Java's reflection mechanism to instantiate its NamingService, explains the fundamentals of reflection, compares alternative approaches, and analyzes the architectural reasons behind choosing reflection in the Nacos client design.
This guide explains how to install the MySQL driver for Python, establish a connection to a MySQL database using MySQLdb, execute queries, and optionally use ORM libraries such as SQLAlchemy or Peewee for higher‑level database interactions.
This article analyzes the limitations of Trip.com’s blocking‑IO servlet architecture for its email push service, proposes a reactive, non‑blocking redesign using EventLoop and NIO, details the thread‑model and code changes, and demonstrates performance gains through benchmark comparisons.
This article explains the complete kernel‑level implementation of the TCP three‑way handshake, covering server listen queue allocation, client connect state handling, SYN/SYN‑ACK processing, syncookie protection, timer management, socket creation, and the accept path, with detailed code examples.
This article explains how SpringBoot launches an embedded Tomcat server by walking through the main method, the SpringApplication.run workflow, context creation and refresh, and the internal Tomcat components such as Connector, Engine, Host, Context, and Wrapper, illustrated with code snippets and diagrams.
This article explains the PHP function image_type_to_extension, describing its purpose, parameters, return value, and provides a complete example showing how to obtain the correct file extension for a given IMAGETYPE constant when saving images.
This article explains what RPC is, walks through each step of a remote procedure call—including stubs, routing, load balancing, serialization, encoding, and network transmission—and analyzes where latency originates to guide backend developers in performance optimization.
This article demonstrates how to use Spring's BeanUtils.copyProperties method to copy properties between objects and provides a generic utility to convert a list of source objects into a list of target objects, illustrated with Java code examples for User and Employee classes.
This guide explains how to integrate Alipay’s new secure transfer API (alipay.fund.trans.uni.transfer) into a Java Spring application, covering SDK upgrade, certificate placement, configuration files, Maven dependency, bean injection, and utility classes with full code examples for payment and transfer operations.
This article explains the purpose and inner workings of Spring's @Transactional annotation, detailing how AOP creates proxy objects, the role of BeanPostProcessor, advisors, interceptors, and the TransactionInterceptor, and walks through key source code snippets that manage transaction boundaries.
getimagesizefromstring is a PHP function that extracts an image’s width and height from raw image data supplied as a string, mirroring getimagesize but accepting string input; the article explains its parameters, return values, and provides example code comparing file‑based and string‑based usage.
The article explains PHP's getimagesize() function, which determines the dimensions, type, and MIME information of various image formats, describes its return values, and provides a complete code example demonstrating how to retrieve image size and output the image with appropriate headers.
This article outlines the design principles, layered and cluster architecture, technical requirements, caching strategies, and payment integration of a cloud‑based shopping cart system, highlighting how distributed backend components ensure stability, high performance, elasticity, and anti‑fraud measures.
This article walks through the concepts, protocols, and complete Go code needed to implement both HTTP and HTTPS forward proxies, explaining request handling, header transformations, and TCP forwarding while providing clear diagrams and runnable examples.
This article examines the challenges faced by a search middle platform—such as inaccurate impact assessment, unstable underlying clusters, and missing process standards—and details a comprehensive quality‑assurance strategy that includes baseline test suites, stability practices, performance testing, emergency drills, and systematic monitoring to ensure reliable search services.
This article explains how to build a real‑time game leaderboard using Redis sorted sets, covering ranking categories, composite scoring formulas, dynamic updates, efficient data retrieval with pipelines, and provides a complete PHP class implementation.
This article traces the evolution of a high‑concurrency backend architecture from a single‑machine setup to cloud‑native microservices, detailing ten‑plus stages such as separating Tomcat and DB, adding caches, load‑balancing with Nginx/LVS, read‑write splitting, sharding, containerization, and finally deploying on public cloud, while also summarizing key design principles.
This article explains the simple factory pattern, compares its standard definition with Nacos's implementation, and walks through concrete Java examples showing how NacosFactory, NamingFactory, and related services create instances in the Nacos client.
The PHP scandir function returns an array of filenames and sub‑directories from a given directory, optionally sorted in ascending or descending order, and can accept a stream context, providing FALSE on failure and generating a warning if the path is not a directory.
This article outlines the step-by-step evolution of server‑side architecture from a single‑machine setup to a cloud‑native, micro‑service ecosystem, detailing concepts such as distribution, high availability, caching, load balancing, database sharding, containerization, and the principles guiding scalable, resilient backend systems.
This article introduces RabbitMQ's core concepts, compares AMQP with JMS, outlines its key features, and demonstrates four working patterns—work queue, routing, publish/subscribe, and wildcard—through detailed Java producer and consumer code examples.
RSocket is a binary, back‑pressure‑aware protocol that supports four interaction models—fire‑and‑forget, request‑response, request‑stream, and request‑channel—using multiplexed frames with odd/even stream IDs for true bidirectional communication, and provides a reactive, resumable API suitable for microservices, IoT, and broker‑based architectures.
This article details the design and implementation of a reactive API gateway built on RxNetty, covering its overall architecture, request dispatch, conditional routing for gray releases, API management, rate limiting, circuit breaking, security policies, and integrated monitoring and tracing capabilities.
This guide walks you through installing Django, creating an app, defining a custom user model with a manager, configuring AUTH_USER_MODEL, and migrating the database, enabling email‑based authentication and flexible user fields.
This article explains PHP's opendir function, which opens a directory handle for subsequent closedir, readdir, and rewinddir operations, details its parameters and return values, and provides a complete example script demonstrating how to read directory contents and output file names with their types.
This article explains the purpose, scenarios, and detailed implementations of common rate‑limiting algorithms—including counter (fixed window), sliding window, token bucket, and leaky bucket—highlighting their advantages, drawbacks, and sample Python code for each.
This article explains how to implement a simple multi‑way merge sort in PHP to sort a massive 1 GB file using only 100 MB of memory, detailing the file‑splitting, incremental merging steps, and providing a complete PHP code demo.
This article explains the background of RSocket and Dubbo 3.0, introduces the spring‑retrosocket project, and provides a detailed, code‑rich tutorial on creating an RSocket server and client in Spring Boot, including dependency setup, configuration, annotations, and testing examples.
This article walks through a rapid three‑day Go onboarding, covering installation, environment setup, core syntax, package management with Go modules, common development tools, and a simple producer‑consumer concurrency example, while comparing Go concepts to Java and JavaScript.
The article explains the PHP getcwd() function, its return values, permission considerations on Unix variants, and provides a clear code example demonstrating how to obtain and change the current working directory using echo and chdir.
This article explains how microservices communicate via inter‑process communication, covering interaction patterns (one‑to‑one, one‑to‑many, synchronous and asynchronous), API definition and evolution, strategies for handling partial failures, and the choice of messaging or request/response technologies such as REST and Thrift.
This article explains why Swagger‑Dubbo is needed, introduces Swagger, describes the Swagger‑Dubbo tool, provides step‑by‑step integration instructions with Maven dependencies and Java configuration code, demonstrates how to launch and test the generated API docs, and outlines additional integrations with Knife4j and YApi.
This article explains how to design and implement a task‑orchestration workflow using a directed acyclic graph (DAG) in Java, covering graph representation, core data structures, concurrency handling with executors, persistence to a database, and platform‑level visualisation.
The article examines how to prevent data inconsistency during cross‑service money transfers by using local transactions, two‑phase commit, and message‑queue based eventual consistency, providing detailed code examples, performance considerations, and practical solutions for large‑scale backend systems.
The article explains PHP's dir() function, detailing its parameters, return values, and providing a complete example that demonstrates opening a directory, retrieving its handle and path, iterating over entries, and closing the directory resource.
This guide explains Nginx's rate‑limiting feature, covering its leaky‑bucket algorithm, basic and advanced configurations—including limit_req_zone, limit_req, burst, nodelay, whitelisting, logging, and custom error codes—to help you protect upstream servers and mitigate abuse.
This article explains what coroutines are, compares them with threads, outlines when to use them, introduces the async‑capable httpx library, shows installation and sample code, and demonstrates a performance test where asynchronous requests cut execution time by about 73% compared to synchronous requests.
This article explains how adopting ten essential microservice best practices—such as single responsibility, independent data stores, asynchronous communication, circuit breakers, API gateways, backward‑compatible APIs, versioning, dedicated infrastructure, independent release pipelines, and organizational efficiency—helps build a loosely‑coupled, scalable, and maintainable backend system.
PHP 8.1 has entered Alpha, introducing enums, fsync/fdatasync, Fibers, expanded resource-to-object conversion, macOS process renaming, new hashing algorithms, enhanced Sodium encryption, inheritance cache, and performance tweaks, with a release schedule leading to a GA version expected by November 2021.
The PHP closedir function closes a directory handle opened by opendir, accepting a resource parameter and returning TRUE on success or FALSE on failure, with usage examples and parameter details for backend filesystem operations.
This guide walks through adding Spring Boot Actuator to a project, configuring default and custom endpoints, securing shutdown operations, and demonstrates practical code snippets and curl commands for monitoring and managing a Spring Boot application.
This article explains the core differences between Java NIO and traditional IO, introduces the concepts of channels and buffers, describes buffer state management, provides a complete NIO selector code example, and compares the NIO workflow with Netty's model.
This article explains how to design and deploy a highly available Redis architecture using Sentinel, covering failure scenarios, evaluation of common HA solutions, step‑by‑step configurations from a single‑node setup to a three‑Sentinel deployment, and practical tips such as using virtual IPs for seamless client access.
The article explains PHP's chroot function, detailing its purpose of changing the process root directory, required environment and permissions, parameters, return values, and provides a practical code example demonstrating its usage.
This article provides a detailed English overview of Netty's complete server lifecycle, covering service startup, connection establishment, data read/write handling, business logic processing, and the procedures for closing connections and shutting down the service.
At Meituan’s 63rd Tech Salon, experts detailed how the company is platformizing its in‑store operations—unifying supply‑chain, transaction, settlement and CRM systems across food delivery, hotels, tickets and lifestyle services—to achieve scalable, reusable, user‑friendly solutions, sharing hard‑won lessons and outlining future integration plans.
This article reviews the evolution of Vivo's e‑commerce promotion system, detailing why the original monolithic architecture failed, how a separate, highly extensible promotion service was designed, the technical challenges of scalability, high concurrency, and stability, and the practical lessons learned from Redis and hotspot key issues.
This article dives deep into the Linux kernel implementation of the listen system call, explaining how the kernel creates and initializes the full‑connection and half‑connection queues, how backlog and system parameters interact, and why these steps are essential before a server can accept client connections.
The article introduces the DCS_FunTester framework, explains its naming, provides Swagger API access, details local deployment steps, describes a header‑based authentication change, outlines asynchronous test execution, multi‑request handling, progress tracking, and includes relevant Java code snippets for building and running the system.
The article explains PHP's cal_days_in_month function, detailing its purpose, parameters (calendar, month, year), return value, and provides a complete example showing how to retrieve and display the number of days in a specific month of a given year.
This article explains the concept of idempotency in API design, why it matters, two main strategies to achieve it, and how global unique identifiers such as UUID and Snowflake can be used to guarantee single‑execution semantics while maintaining performance and scalability.
This article provides a comprehensive overview of e‑commerce order system roles, core modules, workflow design, process engine, state machine, and future architectural evolution, offering practical guidance for building scalable and maintainable order management platforms.
