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.
This article explains how to use the MyBatis @MapKey annotation to map query results into a Java Map, provides a concrete code example, and delves into the internal processing steps—including MapperProxy, MapperMethod, MethodSignature, and DefaultMapResultHandler—that enable this functionality.
This article explains why a Java method that returns a value inside a try block still yields the original value when a finally block modifies the variable, using bytecode inspection, protection mechanisms, and JVM exception‑table behavior to reveal the underlying execution order and performance implications.
A Java rule‑engine experiences occasional 1‑2 second Young GC pauses after warm‑up, caused by dynamic promotion thresholds that trigger massive object promotion, and the article explains the root cause, demonstrates log analysis, and provides JVM tuning steps to eliminate the long pauses.
This article explains how to redesign a Java data model so that a single sessionId is stored at the outer level while multiple sceneId/sceneName pairs are nested inside a sceneList, and shows the required MyBatis mapper, XML mapping, service, and controller implementations.
This article introduces MyBatis‑Flex, a lightweight and high‑performance MyBatis enhancement framework, outlines its key features, compares it with similar tools, presents benchmark results, lists supported databases, and provides a step‑by‑step quick‑start tutorial with complete code examples for Spring Boot integration.
This guide explains how Spring Boot 3.2 leverages the OpenJDK CRaC project to create and restore JVM checkpoints, dramatically reducing application startup time through automatic and manual checkpoint techniques, complete with required dependencies, installation steps, and performance results.
This article explains how to mask sensitive fields in Java logs, demonstrates the pitfalls of shallow‑copying nested Maps during masking, and shows a robust solution using Guava's Maps.transformEntries to perform lazy, view‑based deep transformation without mutating the original data structures.
This article walks through a Java junior's code review, showing step‑by‑step how simple null‑checks evolve into constant definitions, static methods, enums, Optional usage, and finally strategy‑pattern implementations, illustrating both useful refactoring and the risk of over‑design.
This article explains how to deploy and use Alibaba Canal to capture MySQL binlog changes, configure MySQL and Canal, and write Java code that listens to row‑level events for synchronizing data to other systems such as Redis or Elasticsearch.
This article examines how MySQL's JDBC driver manages ResultSet resource release, the internal close mechanisms, and the concurrency limitations of Statement objects, illustrated with code excerpts and a Groovy virtual‑thread demo that reveals runtime exceptions when ResultSets are accessed after implicit closure.
This article analyzes a Spring MVC issue where a batch template download failed due to missing configuration, explores how @ResponseBody interacts with manual stream writes, presents code examples, debugging insights, and offers best‑practice recommendations for reliable file‑download endpoints.
This article provides a step‑by‑step guide on integrating Spring Batch with Spring Boot, covering business scenarios, database setup, Maven dependencies, configuration of JobRepository, JobLauncher, Job, Step, ItemReader, ItemProcessor, ItemWriter, listeners, validators, execution via REST endpoints, troubleshooting with Druid and switching to HikariCP, and demonstrates processing CSV and database data in large batches.
This article explains why retry mechanisms are essential for distributed Java applications and walks through eight practical implementations—including loop, recursion, Apache HttpClient, Spring Retry, Resilience4j, custom utilities, asynchronous thread‑pool retries, and message‑queue based retries—plus best‑practice guidelines to avoid common pitfalls.
RediSearch, a low‑memory Redis module, offers comparable full‑text search capabilities to Elasticsearch, with faster indexing and query performance on modest hardware; this article explains its features, compares benchmarks, shows Docker installation, and provides Java/Jedis code examples for creating, querying, and managing indexes.
This article presents Qunar Travel's "system slimming" project, describing how observability techniques, a two‑stage strategy, and automated tooling were used to identify and remove unused services and code, achieving a 50% reduction in code size, a 26% cut in services, and measurable improvements in reliability and release efficiency.
This article explains the concept of idempotency, outlines common strategies, and provides a complete Spring Boot implementation that uses Redis, a custom @AutoIdempotent annotation, token generation, and a web interceptor to ensure each API request affects the database only once.
This article provides a comprehensive guide to KafkaConsumer, covering message delivery semantics (at‑most‑once, at‑least‑once, exactly‑once), practical exactly‑once implementations, consumer rebalance triggers and strategies, partition assignment algorithms, thread‑safety considerations, and detailed Java code examples of the consumer workflow.
This tutorial walks through advanced Spring Cloud Function features—including handling HTTP request parameters, function mapping and filtering rules, functional bean definitions, visualization via Actuator, and package scanning—providing code examples and configuration tips for Spring Boot 2.7.15 projects.
This article explains why Java processes in Kubernetes pods often encounter OOMKilled despite correct JVM heap settings, analyzes the discrepancy between JVM‑reported memory and container metrics, and provides practical steps such as adjusting MaxRAMPercentage and pod memory limits to stabilize memory usage.
This article walks through the complete process of adding Dataway to a Spring Boot application, covering Maven dependencies, configuration properties, database schema creation, data source setup, Hasor module integration, enabling Hasor in Spring, and finally creating and testing API endpoints using both SQL and DataQL, all illustrated with concrete code snippets and log output.
The paper presents a centralized online batch‑processing framework for large‑scale promotion systems, where applications integrate via an SDK, a task‑center schedules and dispatches sub‑tasks through RocketMQ to Dubbo‑enabled containers, employing MapReduce‑style splitting, Guava rate‑limiting, heartbeat health checks, and has successfully handled over 1.3 million tasks during Double‑11.
This article examines common Java jar obfuscation tools, identifies their limitations for protecting both proprietary code and third‑party dependencies, and proposes a lightweight Maven‑based encryption combined with a runtime agent that decrypts classes on demand while keeping performance impact under five percent.
This article explains the underlying principles and step‑by‑step configuration for integrating Spring Boot with MyBatis to manage multiple data sources, covering BeanFactory, FactoryBean, SqlSessionFactoryBean setup, datasource properties, mapper scanning, and sample controller code for accessing distinct databases.
An in‑depth analysis reveals how the JDK’s DiscardPolicy rejection strategy can cause invokeAll to block indefinitely, exposing a subtle thread‑pool bug, the official response, and practical code examples demonstrating the issue and ways to avoid it.
Spring 6 offers four powerful ways to perform remote HTTP calls—WebClient, RestTemplate, HTTP Interface, and RestClient—each with distinct APIs, configuration options, and usage patterns, and this guide walks through their setup, method signatures, request handling, and error management for Java developers.
This article provides a comprehensive overview of the Caffeine local cache library, covering its fundamentals, configuration options, loading strategies, eviction policies, statistics, and detailed steps for integrating Caffeine with Spring Boot using annotations and custom cache managers.
This guide explains why thread pools are essential in Java, walks through factors such as CPU cores, I/O latency, and workload characteristics, and provides formulas and concrete code examples for calculating the ideal pool size for both CPU‑bound and I/O‑bound tasks.
A seasoned Java engineer shares his journey transitioning to Rust, highlighting Rust’s advantages for CLI tools, superior resource utilization, easier concurrency and async programming, while also acknowledging Java’s strengths in rapid feature delivery, mature ecosystem, and ease of learning, and discussing practical migration considerations.
This article presents more than ten practical techniques for writing faster, cleaner Java for‑loops, covering basic size caching, reverse iteration, iterator usage, enhanced for‑loops, nested loop reduction, exception handling placement, and method‑call minimization to improve overall program performance.
This article explains various web message‑push techniques—including short and long polling, iframe streaming, Server‑Sent Events, MQTT, and WebSocket—provides detailed Java and JavaScript code samples, compares their trade‑offs, and shows how to integrate them in a Spring Boot application.
This article introduces the PowerJob distributed task framework, explains why it was chosen, details its architecture and high‑availability design, demonstrates various job types—including standalone, broadcast, map, and map‑reduce—with Java code examples, and covers scheduling options such as CRON, fixed‑rate, and fixed‑delay execution.
This article explains the Spring MVC return‑value handling mechanism, demonstrates how to implement a custom HandlerMethodReturnValueHandler, register it correctly in a WebMvcConfigurer, and troubleshoot why the default processor may override custom handlers.
Graceful Response is a Spring Boot component that unifies response wrapping, global exception handling, and custom error codes, helping developers reduce boilerplate, improve readability, and accelerate API development while supporting validation and customizable response styles.
The article reviews a Scala meetup where experts compare Java and Scala, highlighting Scala's stronger expressiveness, type inference, pattern matching, safety, and concurrency features, and discusses real‑world adoption, developer experiences, and a recruitment opportunity for a Scala‑focused big‑data team.
This article walks developers through Sermant’s architecture, explaining its plugin mechanism, class isolation, and how to build practical plugins with basic capabilities, unified dynamic configuration, and unified logging, while showcasing real‑world examples and tips for efficient development.
This article explains how positioning a try‑catch block either inside or outside a Java for loop changes exception handling behavior, performance impact, and when to choose each approach based on business requirements.
This article demonstrates how to enable and use Coordinated Restore at Checkpoint (CRaC) in Spring Boot 3.2 with the Spring Petclinic example, covering required dependencies, JVM setup, automatic and manual checkpoint creation, performance measurements, and best‑practice considerations for backend developers.
Switching a Java Netty gateway from GZIP to ZSTD compression using zstd‑jni doubled GC time and introduced heap and Netty off‑heap memory leaks, which were resolved by employing the library’s direct off‑heap API with a NoFinalizer compressor, promptly releasing ByteBufs, avoiding finalize(), and adopting jemalloc to reduce fragmentation.
Using Jackson's ObjectMapper for JSON parsing, this article benchmarks three approaches—creating a new mapper per call, sharing a global singleton, and using ThreadLocal—revealing that a single shared ObjectMapper can achieve up to ten times higher throughput, while ThreadLocal offers only modest gains.
A Java backend developer investigates why an enum‑based status field becomes an empty string during database insertion, tracing the issue through code inspection, Arthas watches, and ultimately discovering a mis‑implemented enum setter caused by a third‑party library.
This article explains Spring's control flow pointcuts, compares them with AspectJ cflow pointcuts, walks through a complete Java example with nested service classes, shows how to configure a ControlFlowPointcut and proxy, and discusses performance implications and usage scenarios.
This article compiles a comprehensive list of IntelliJ IDEA shortcuts, configuration tweaks, and useful plugins—including history navigation, memory settings, Eclipse keymap, code inspection, bookmark management, Maven helpers, and multi‑port debugging—to boost Java developers' productivity and streamline their workflow.
This article reviews Oracle's Java 21 LTS release, outlines its new JEP features, compares it with Java 17, shares upgrade experiences including pom updates and runtime fixes, and evaluates generational ZGC and virtual threads with performance tests and code examples.
Java’s traditional synchronous blocking model wastes thread resources during I/O, leading to scalability limits, while asynchronous, reactive, and especially Java 21’s virtual threads offer non‑blocking execution paths that improve performance and simplify development without complex reactive pipelines.
This tutorial demonstrates how to create a universal CSV/Excel export utility in Java that can handle objects of any class by using reflection to generate headers and rows, leveraging Apache POI and Spring Boot for seamless file generation.
This article provides a comprehensive overview of the lightweight XXL‑RPC framework, covering fundamental RPC concepts, the framework's architecture built on Spring and Netty, detailed provider and consumer implementations, various call types, and the service registry‑discovery mechanism, concluding with practical insights for developers.
This article introduces the Lock4j distributed lock library for Java, outlines its key features and supported backends, provides step‑by‑step Maven dependency setup, Redis configuration, annotation details, and demonstrates both basic and advanced usage patterns including custom executors and lock‑failure strategies.
This tutorial shows how to build a lightweight request‑tracing solution in SpringBoot 3.2 using SLF4J, MDC, custom filters, logback configuration, and a global ResponseBodyAdvice to log and return trace IDs for improved debugging and observability.
Microsoft reports over 2.5 million Java developers using VS Code and outlines a new roadmap, while this guide walks you through installing the JDK, adding the Java extension pack, and creating Java projects in VS Code with troubleshooting tips.
This article provides a comprehensive guide to MyBatis dynamic SQL tags—including foreach, if, where, choose, trim, set, and selectKey—showing how to build flexible queries, handle collections, and avoid common pitfalls with clear code examples and best‑practice explanations.
The article describes a Groovy scripting issue where calling StringBuilder.setLength(0) triggers a NoSuchMethodError, explains Groovy's automatic property generation, demonstrates debugging steps, metaprogramming attempts, and the final workaround that resolves the error.
Learn how to dramatically reduce startup time in large Spring applications by using spring-context-indexer to generate component indexes at compile time, configure Maven or Gradle dependencies, create manual or IDE‑generated index files, support custom annotations, and disable indexing when needed.
Facing uncontrolled log proliferation, the author shares a real-world case of log governance that reduces costs and boosts efficiency by categorizing logs, simplifying formats, consolidating tools, introducing a three‑layer log architecture, and applying stack‑trace reversal techniques with concrete code examples.
This article explains how to implement unified exception handling in Spring Boot applications using @ControllerAdvice, custom Assert utilities, and enum-based error codes, demonstrating code examples, response structures, and best practices for reducing try-catch clutter, improving readability, and handling various HTTP and business exceptions consistently.
