This article explains the concept, advantages, and implementation methods of Single Sign‑On (SSO) and provides two complete hands‑on examples—including architecture diagrams, database schema, configuration, and Java code for token‑based, ticket‑based, and RSA/AES encrypted SSO flows—using SpringBoot, Vue and Uni‑App.
This article presents a Java-based rule engine design, illustrating rule abstraction, concrete rule implementations, and a flexible executor supporting AND/OR logic, accompanied by code examples and a discussion of its advantages and drawbacks for maintainability.
This article introduces Java 8 Stream API, explains how to create streams from collections, demonstrates common intermediate operations such as filter, map, flatMap, limit, skip, distinct, sorted, peek, and shows terminal actions like forEach, count, max, min, findFirst, findAny, and match methods with practical code examples.
This article compiles common technical interview questions for bank software positions, covering Java fundamentals, MySQL storage engines and indexes, thread‑pool parameters, HTTP GET/POST differences, TCP vs UDP characteristics, session and cookie handling, Redis data types, and C++ memory management, providing concise explanations and examples for each topic.
The article first presents a detailed analysis of Tencent's 2024 campus recruitment salary packages for various programmer offers, then introduces a classic algorithmic challenge of reversing a linked list in groups of k nodes, providing step‑by‑step explanation and a complete Java implementation.
The article outlines how the Taobao “Calm Guard” project accelerates rapid‑iteration development by employing reusable patterns—including a Spring‑based Strategy registry, a hierarchical fatigue‑control framework, generic cache upsert via functional parameters, and precise AOP aspects—resulting in faster, more stable, and maintainable code.
This article presents a curated list of the twelve most popular Java open‑source projects on GitHub in May 2023, providing repository URLs, star counts and concise descriptions to help developers discover valuable resources across backend, cloud‑native, and data‑integration domains.
This tutorial walks through Spring AOP's control flow pointcuts and introduction advice, showing how to define dynamic pointcuts, create advisors, and use @DeclareParents to add interfaces to beans, complete with practical code examples and output analysis.
This article explains how to design and implement a distributed rate‑limiting solution that supports multiple concurrent rules—such as per‑minute and per‑hour limits—by analyzing the shortcomings of simple string counters, introducing atomic Lua scripts and Zset structures, and providing complete Java annotation and AOP code examples.
This article details the background, pain points, and step‑by‑step technical solution behind refactoring a massive 670,000‑line, 46‑module ticketing application at Alibaba, highlighting architecture redesign, code simplification, performance gains, and a pragmatic rollout plan.
This article explains how Java's break and continue statements work, demonstrates why a simple break cannot exit nested loops, and shows how to use labeled break (and similarly labeled continue) to terminate all loops at once with clear code examples.
Rate limiting protects system stability by capping request rates, and this article explains five Java algorithms—Fixed Window, Sliding Window, Leaky Bucket, Token Bucket, and Guava's RateLimiter—showing their principles, pros and cons, and providing sample implementations and a Spring @Limit annotation for practical enforcement.
This guide walks through configuring the Alipay sandbox, adding Maven dependencies, setting up application.yml, implementing Java configuration classes, creating controller endpoints for payment, handling asynchronous callbacks, processing refunds, and using RabbitMQ delayed queues to auto‑cancel unpaid orders, all with complete code examples.
This article explains ten practical techniques for implementing robust parameter validation in Spring Boot applications, covering built‑in annotations, custom constraints, server‑side checks, internationalization, validation groups, cross‑field rules, exception handling, testing, and the importance of complementary client‑side validation.
This article explains why traditional LIKE queries fail on encrypted sensitive fields, analyzes common scenarios, and presents four practical solutions—including tokenized ciphertext mapping—along with environment setup, Maven dependencies, and complete Spring Boot code to enable secure fuzzy searches on encrypted data.
Tired of manually creating entity classes, CRUD interfaces and SQL for dozens of tables, the author built an open‑source utility that generates complete backend code—including models, DAOs, services and controllers—in a single click, dramatically cutting development time.
This article explains the definitions, characteristics, and overflow cases of sequential and circular queues and stacks, provides Java implementations for these data structures, demonstrates their usage with sample code and results, and discusses practical applications of queue thinking in database-driven workflows.
This article explains how to monitor, interpret, and optimize Java Garbage Collection by using JDK flags, IDE configurations, and the gceasy.io visualizer, providing step‑by‑step guidance, sample logs, and performance metrics for effective JVM tuning.
This article explains various comparison methods in Java, including equality operators, the equals() method, Comparator and Comparable interfaces, and provides code examples for primitive, object, string comparisons, as well as custom sorting logic, highlighting their roles in sorting, searching, and data handling.
This guide explains why and how to create a custom HttpMessageConverter in Spring Boot 2.7.12, covering the implementation of the converter, its registration in the MVC configuration, testing with Postman, and the underlying request‑response processing mechanism.
This article explains seven subtle issues when using Spring's BeanUtils.copyProperties—such as type mismatches, null overwrites, wrong imports, inner‑class copying failures, shallow copy side effects, and performance drawbacks—providing code examples and recommendations to avoid them.
This article explains the inner workings of Nacos' long‑polling mechanism, covering both client‑side scheduling and server‑side handling, with detailed code walkthroughs, architectural diagrams, and insights into how configuration changes are detected and propagated in a distributed system.
This article introduces four powerful IntelliJ IDEA debugging techniques—adding log statements at breakpoints, using field breakpoints, configuring exception breakpoints, and setting method breakpoints—to help developers efficiently trace code execution and inspect variables without cluttering the source.
Learn how to use Spring's @Nullable annotation (or its Java equivalents) to safely handle missing beans during dependency injection, avoiding startup errors, with code examples, underlying mechanism details, and comparisons to other approaches like required=false, Optional, and ObjectFactory.
This article introduces Java thread pools, explaining their purpose, creation using ThreadPoolExecutor, execution flow, advantages such as resource reuse and management, common blocking queues, rejection policies, and provides multiple code examples of various pool types and a comprehensive monitoring example.
This article introduces mybatis-plus-generator-ui, a highly customizable web‑based code generator built on MyBatis‑Plus that supports multiple databases, offers interactive UI for generating Entity, Mapper, Service, Controller and other layers, and provides detailed usage, configuration, and extension instructions for Java backend developers.
This article presents mybatis-plus-generator-ui, a web‑based code generation framework that wraps MyBatis‑Plus, explains its features, shows how to integrate it via Maven and a Spring Boot entry point, demonstrates customization through templates and NameConverter, and provides guidance for building the UI frontend.
This article explains how Java achieves "write once, run anywhere" through platform‑independent bytecode, describes the .class file structure, introduces tools for viewing bytecode, and provides detailed guidance on using the ASM library’s Core and Tree APIs for bytecode enhancement, including practical code demos and application scenarios.
This article demonstrates five Java thread‑communication approaches—using a volatile flag, Object.wait()/notify(), CountDownLatch, ReentrantLock with Condition, and LockSupport—each illustrated with complete code examples and explanations of their behavior and limitations.
This article explains why RocketMQ messages can pile up, analyzes the consumer pull‑process bottlenecks of consumption latency and concurrency, and provides practical strategies—including logging, JVM stack inspection, and concurrency tuning—to identify and eliminate the root causes of message backlog.
This tutorial explains how to integrate Feign‑reactive into a Spring Boot 2.7 application, covering dependencies, reactive interface definitions, fallback handling, custom configurations, timeout, load‑balancing, and circuit‑breaker settings with complete code examples.
This article explains how to diagnose and dramatically reduce SpringBoot service startup latency by examining SpringApplicationRunListener phases, Bean scanning overhead, BeanPostProcessor timing, and cache auto‑configuration, then applying JavaConfig and starter‑based solutions to cut startup from minutes to seconds.
This article explains how to install pycryptodome (or pycryptodomex) to perform SM2 signing and verification in Python, provides complete code examples, and offers guidance for ensuring compatibility with Java's Bouncy Castle SM2 implementation.
This article explains the concept of idempotency, why it is essential for API reliability, and demonstrates four practical idempotency strategies—including database primary keys, optimistic locking, token validation, and Redis caching—implemented via custom annotations and the Strategy pattern in a Spring‑Boot Java project.
Jedis uses Apache Commons’ GenericObjectPool to manage Redis connections, with Spring‑Data‑Redis creating a JedisConnectionFactory that holds a configurable pool where borrowObject and returnObject handle idle queues, eviction and validation settings (testOnBorrow, testWhileIdle, etc.) can be tuned, and JMX metrics aid troubleshooting.
This article explains how to dynamically modify Cron expressions for scheduled tasks in SpringBoot applications, covering @EnableScheduling, @Scheduled, mutable and immutable task configurations, custom interfaces, and code examples for registering, refreshing, and managing tasks at runtime without external schedulers.
The article details a step‑by‑step investigation of a Spring Boot service that failed to meet a 500 requests/second target, analyzes slow SQL, thread‑pool misconfiguration, excessive logging, and high CPU usage, and presents concrete optimizations that roughly doubled throughput.
This article explains how to implement a hot‑plugable AOP mechanism in Spring that lets end users enable or disable logging advice at runtime by dynamically adding or removing Advice, Advisor, and Proxy definitions through custom endpoints and event listeners.
This article explains how to classify interface exceptions, implement unified handling using Spring Boot's @ControllerAdvice and custom ErrorController, and provides practical code examples for business, system, client, and filter exceptions, including redirect and error page strategies.
This article explains how JVM synchronized locks and MySQL row locks can interact to cause deadlocks, demonstrates the problem with sample Spring code, shows the resulting lock‑wait timeout exception, and provides a refactoring solution to avoid the deadlock.
This article explains how the open‑source AutoDev plugin builds an end‑to‑end AI‑assisted coding solution that fine‑tunes open LLMs, constructs a Unit Eval dataset, engineers prompts for unit‑test generation, and enforces quality through a unified write‑evaluate pipeline.
This article walks through the painful migration from Apache HttpClient 4.x to 5.3, detailing modular design, customization, HTTP/2 support, connection management, API changes such as retry strategy, request/response configuration, interceptors, async client, and provides concrete Maven snippets and code comparisons to help developers evaluate whether the upgrade is worthwhile.
This article walks through multiple ways to add text or image watermarks to PDF files in a Spring Boot application, covering Apache PDFBox, iText, Ghostscript command‑line, Free Spire.PDF, and Aspose.PDF, with Maven dependencies, step‑by‑step code examples, and practical tips for preserving original documents.
This article explains how to set conditional breakpoints in IntelliJ IDEA to skip unnecessary iterations during debugging, illustrating the technique with a Java loop example and highlighting its usefulness for locating issues in complex code structures.
This article revisits defensive programming, explores quirky variable‑naming techniques—including single‑character, Chinese, and multilingual identifiers—and humorously breaks down core OOP concepts while stressing the developer’s irreplaceable role in modern software projects.
This article explains how to set up WebSocket communication in Spring Boot 2.7.12, covering the protocol basics, handshake process, custom HandlerMapping, annotation-driven routing, and a reactive WebFlux handler with code examples, plus deployment considerations behind reverse proxies.
The article compares interview questions from ten years ago, which focused on basic Java concepts, with today's interviews that probe deep system design, distributed architecture, performance troubleshooting, and data consistency, highlighting the increasing difficulty and breadth of knowledge required for modern developers.
This article explains the fundamental concepts of processes and threads, uses a gaming analogy to illustrate their relationship, and details three ways to create threads in Java—extending Thread, implementing Runnable, and implementing Callable—along with common thread control methods such as sleep, join, and setDaemon.
This article outlines common pitfalls of using Spring's BeanUtils.copyProperties for object property copying in Java backend development, including type mismatches, null overwrites, incorrect imports, inner class issues, shallow copy behavior, and performance drawbacks, and advises caution when employing this utility.
This article introduces Spring Boot 3.2's new JdbcClient, explains its fluent API style, shows how to add the dependency, inject it, and perform various query and insert operations with code examples, highlighting its advantages over traditional ORM frameworks.
This article provides a detailed, global‑level review of MyBatis, covering its main features such as SQL mapping, dynamic SQL, parameter and result mapping, transaction management, connection‑pool integration, second‑level cache, as well as the three‑layer architecture, configuration parsing, proxy creation, and SQL execution process.
This guide explains how MSE Nacos integrates with Alibaba Cloud KMS to encrypt and protect sensitive configuration data, covering the security challenges, architecture, encryption/decryption workflows, recommended configuration items, step‑by‑step setup, and Java/Go SDK examples for cloud‑native applications.
This article explains how to build a high‑performance file chunk (slice) upload system using Spring Boot and MinIO, covering project setup, MinIO configuration, controller and service implementation, front‑end integration with Thymeleaf, and performance optimizations such as parallel uploading and resumable transfers.
This article evaluates the performance of large language model (LLM) inference on the Java platform, examining llama2.java implementations that leverage Java Streams, the Vector API, Project Panama, and TornadoVM GPU acceleration, and compares them against native C versions across various model sizes.
This article introduces the MyBatis-Plus Generator UI, a web‑based tool that streamlines Spring Boot code generation for entities, mappers, services, and controllers, explains how to integrate it via Maven, configure databases, customize templates, and extend its functionality with custom name converters.
JustAuth is a Java library that simplifies third‑party OAuth login by providing unified interfaces, customizable state, scopes, HTTP clients, and support for dozens of platforms, with clear code examples for quick integration such as QQ login.
This guide introduces Spring Boot 3.2's new JdbcClient, explains how to add the dependency, inject it, and perform fluent, chainable CRUD operations—including queries by ID, custom conditions, named parameters, map parameters, row mapping, and inserts—while highlighting its advantages over traditional ORM tools.
This guide demonstrates five practical Spring Boot 3 techniques—including using @ConfigurationProperties with validation, handling missing @Value entries, defining custom property sources, enforcing required properties, and parsing YML files—to ensure robust configuration management and prevent startup failures.
This article explains a three‑step method—using top to locate the CPU‑hungry Java process, identifying the offending thread, and printing its stack with jstack—to pinpoint and resolve excessive CPU consumption in a Java application running on Linux.
This article compiles essential backend interview questions and answers covering MySQL storage engines and indexes, Redis persistence modes, Java collection frameworks and HashMap internals, thread‑safe ConcurrentHashMap implementations, as well as HTTP message structure and TCP reliability mechanisms, providing a thorough review for candidates preparing for backend positions.
The article explains the concept of delayed tasks versus scheduled tasks in payment systems, outlines their key differences, and evaluates five practical implementation approaches—Quartz database polling, JDK DelayQueue, Netty's HashedWheelTimer, Redis ZSET/Keyspace notifications, and RabbitMQ delayed queues—detailing their code examples, advantages and drawbacks.
This article explains why traditional file uploads struggle with large files, then introduces three advanced techniques—instant (秒传), chunked (分片上传), and resumable (断点续传) uploads—detailing their core logic, implementation steps, and Java code examples for backend developers.
This article explains why rate limiting is essential for high‑traffic systems, defines common rate‑limiting algorithms (fixed window, sliding window, leaky bucket, token bucket), provides complete Java code examples for each, and demonstrates practical usage with Guava's RateLimiter in real‑world applications.
This article explains how Spring WebFlux's functional programming model uses HandlerFunction, ServerRequest, and ServerResponse to build reactive, immutable HTTP endpoints, covering routing with RouterFunction, request body extraction, response creation, validation, and practical code examples for Java developers.
This guide explains why Spring Boot 2.7 is the optimal bridge to JDK 17, details the new language and performance features, provides step‑by‑step deployment and configuration instructions for JD Cloud, and shares practical compatibility fixes and IDE tips for a smooth migration.
This article explains how to build a high‑performance, million‑row Excel export feature in Java using SpringBoot, EasyExcel, asynchronous job or MQ processing, pagination, multi‑sheet handling, OSS storage, and WebSocket notifications to avoid timeouts, OOM errors, and improve user experience.
This article explains MyBatis's first‑level and second‑level cache mechanisms, illustrates common consistency problems caused by default cache settings in both distributed and single‑session scenarios, and provides practical recommendations such as adjusting localCacheScope or deep‑copying results to avoid cache pitfalls.
This article provides a detailed walkthrough of Nacos' configuration center long‑polling mechanism, explaining how the client initializes ConfigService, schedules periodic checks, processes configuration changes, and how the server receives listener requests, manages long‑polling tasks, and triggers change events, all illustrated with code snippets and diagrams.
This article explains why using the == operator on two Java Integer objects can yield true for values between -128 and 127 but false for larger numbers, detailing the Integer cache mechanism, reference vs value comparison, and the proper use of equals for value equality.
This article analyzes the inefficiencies and duplication in typical Spring Boot controller code, introduces the Graceful Response library, and provides step‑by‑step instructions—including Maven integration, annotation setup, controller and service examples, exception mapping, validation handling, and response style configuration—to achieve cleaner, unified API responses.
This article explains how to dynamically modify Cron expressions for scheduled tasks in a SpringBoot application by using @EnableScheduling, @Scheduled, custom interfaces, and a refresh mechanism that registers, updates, or disables tasks at runtime without additional middleware.
This article explains how to enable and use the OpenJDK CRaC project with SpringBoot 3.2, covering prerequisites, dependency setup, automatic and manual checkpoint creation, and demonstrates significant startup‑time reductions through detailed examples and performance results.
This article benchmarks the cost of instantiating a new ObjectMapper for each JSON conversion in a SpringBoot project, demonstrates a singleton implementation that boosts read performance by 18× and write performance by up to 300×, and shows how to add custom serializers without sacrificing speed.
This article walks through the complete design and implementation of a permission module for the Mall e‑commerce project, covering functional design, database schema, API specifications, and key technical choices such as Spring Security, JWT, and Redis‑based AOP optimization.
This guide explains how to protect Spring Boot production packages from reverse engineering by applying code obfuscation with ProGuard and full encryption using the ClassFinal Maven plugin, including configuration steps, encrypted startup commands, machine‑binding activation, and the resulting decompilation behavior.
This article introduces Java multithreading, covering core concepts such as thread lifecycle, creation via Thread subclass and Runnable, synchronization mechanisms, thread pools, and practical applications in web, Android, game, and big data development, helping readers fully grasp multithreaded programming in Java.
This article explains the concept, advantages, and three implementation methods of Single Sign-On (SSO), then provides two complete practical examples—including architecture diagrams, step‑by‑step flows, and full Java code for ticket‑based and encrypted data‑based SSO—followed by supplementary RSA key generation notes and a brief promotional note.
The article explains a junior developer's intermittent bug when adding a new order status with code 200, showing that Java's Integer cache and the use of == instead of equals cause the status check to fail, and provides the correct solution.
This tutorial explains why auditing is essential, outlines the benefits such as data tracking, security, troubleshooting and compliance, and provides a complete Spring Data JPA implementation with code examples, testing procedures, and required dependencies.
After upgrading to IntelliJ 2023.3 for better JDK 21 virtual‑thread support, users encounter a Groovyc ClassNotFoundError caused by missing IntelliJ internal classes, and the article outlines the affected builds and three practical work‑arounds, including a JVM option to run Groovyc in‑process.
This guide walks you through building a Spring Boot application that calls the OpenAI ChatGPT API, covering prompt concepts, API request details, required dependencies, configuration of RestTemplate with authentication, DTO definitions, controller implementation, and example use cases.
This article demonstrates how to build a custom dynamic data‑source solution for Spring Boot by using ThreadLocal to store the current datasource key, extending AbstractRoutingDataSource for routing, configuring multiple datasources in application.yml, and optionally adding annotation‑driven switching and runtime datasource registration.
This article explains the concept of idempotency, presents several strategies to achieve it, and provides a complete Spring Boot implementation using Redis, a custom @AutoIdempotent annotation, token generation and verification, interceptor configuration, and test cases to ensure only the first request succeeds.
This article examines the various design patterns—such as Factory, Singleton, Builder, Adapter, Proxy, Composite, Decorator, Template, Strategy, and Iterator—employed within the MyBatis source code, explaining their structures, usage scenarios, and related components to illustrate how the framework achieves modularity and flexibility.
This article explains how to retrieve and handle various Spring Boot API parameters—including query, path, request body, header, and file uploads—covers parameter type handling such as dates and lists, demonstrates validation annotations, and provides complete code examples for each scenario.
This article introduces binary trees, explains their Java representation, demonstrates pre-order, in-order, post-order, and level-order traversals, and provides implementations for creating full binary trees, counting nodes, computing height, and counting leaf nodes, complete with sample code and usage examples.
This article explains Java generics, covering type parameters, generic classes and interfaces, bounded types, wildcards, and generic methods, while highlighting benefits such as type safety, code reuse, readability, and performance, and provides multiple code examples demonstrating generic usage across different data types.
This guide walks through configuring a Spring Boot 2.4.12 project with Elasticsearch 7.8, creating index templates, implementing bulk write operations, and testing the setup with sample code and endpoints, enabling automatic index creation and efficient data ingestion.
This article provides an in‑depth analysis of Druid's connection‑pool lifecycle, covering initialization, connection acquisition, validation, eviction, keep‑alive, and recycling processes, while offering performance‑related configuration recommendations and code examples for Java developers.
When a production container suddenly hit over 90% CPU and excessive JVM garbage collection, the author walks through entering the pod, using top and top‑H to locate the offending thread, extracting its stack with jstack, downloading the data via a simple HTTP server, and ultimately discovering an Excel export routine that caused massive object allocation, fixing the code and restoring stability.
This article explains the core concepts, architecture, and implementation details of the lightweight distributed scheduling platform Xxl-Job, including its scheduler center, executor, job handlers, registration, task triggering, routing strategies, execution flow, and result callbacks, with a step‑by‑step demo and code examples.
This article explains how to protect microservice APIs from tampering and replay attacks by using HTTPS, request signing, nonce‑timestamp mechanisms, and AppId/AppSecret authentication, and demonstrates a complete Java/Spring implementation with a responsibility‑chain based verification filter.
The article enumerates twelve common defensive coding habits—like per‑table microservices, overly long methods, deep nesting, misleading comments, and unnecessary frameworks—that degrade readability and increase maintenance effort, illustrating each with a fictional programmer’s missteps and their impact on teams.
This article introduces the Hutool Java utility library, outlines its core modules, shows how to integrate it via Maven, and provides practical code examples for HTTP requests, random code generation, pinyin conversion, timing, number handling, data masking, email sending, and Bloom filter usage.
This article explains how Spring Cloud discovers classes annotated with @ConfigurationProperties, wraps them into ConfigurationPropertiesBean objects, and dynamically rebinds them at runtime using RefreshScope, EnvironmentChangeEvent, and the RefreshEndpoint actuator, enhancing application flexibility and scalability.
esProc SPL, a pure‑Java, lightweight data‑processing engine, offers richer data source support, built‑in flow control, and easier complex calculations compared to SQLite, making it a powerful alternative for small applications that need database‑like capabilities without the overhead of traditional databases.
Graceful Response is a Spring Boot library that provides unified response wrapping, global exception handling, and customizable error codes, reducing boilerplate code, improving readability, and streamlining validation for Java web APIs.
This guide explains how to implement dynamic data source switching in SpringBoot by leveraging ThreadLocal and AbstractRoutingDataSource, covering basic concepts, code examples for context holder, routing datasource, configuration, annotation‑driven switching, and runtime addition of new data sources with practical testing steps.
This article explains the fundamentals of ThreadLocal, its memory‑leak pitfalls, introduces the new ScopedValue feature in JDK 20, demonstrates practical Spring‑based use cases, and shows how StructuredTaskScope enables safe structured concurrency with code examples.
This article provides a comprehensive technical walkthrough of Nacos as a service registry, covering its core features, architecture components, the underlying registration and health‑check processes, source‑code analysis of Spring Cloud integration, and the detailed service‑discovery workflow.
