Sharing Java and Python tech insights, with occasional practical development tool tips.
This article explains how to set up a dynamic IP blacklist using Nginx, Lua scripts, and Redis, covering environment preparation, design options, configuration of nginx.conf, Lua script implementation, and advanced features such as rate limiting, white‑listing, and automated detection to protect servers from malicious traffic.
This article demonstrates how to create and fill PDF templates using a PDF editor and Java iText library, covering importing Word documents, inserting text, option, and image fields (including signatures and stamps), and provides complete code examples for generating customized PDFs.
This article explains the fundamentals of OAuth2.0, outlines its roles and grant types, and provides a step‑by‑step Spring Boot implementation—including authorization server, security configuration, resource server, and a test controller—followed by detailed testing procedures and results.
The article explains how modern multi‑core CPUs use time slices, hyper‑threading, and various types of context switches to manage multithreaded workloads, discusses the performance costs of switching, and offers practical optimization strategies such as lock‑free programming, appropriate thread counts, and coroutine usage.
This article explains how to implement unified global exception handling in SpringBoot by using @ControllerAdvice with @ExceptionHandler, defining a base error interface, custom enums, exception classes, and a standardized response wrapper, while also providing test code examples and best‑practice recommendations.
This guide details a secure third‑party API design, covering API key generation, request signing with timestamps and nonces, permission division, CRUD endpoint definitions, unified response structures, and best‑practice security measures such as HTTPS, IP whitelisting, rate limiting, logging, and idempotency handling.
This article explains how Spring Framework's ResponseBodyEmitter enables real‑time, chunked HTTP responses for use cases such as log streaming, progress updates, chat, and AI output, detailing its advantages over SSE, usage scenarios, core methods, a complete controller example, and best‑practice considerations.
This article explains how to build a Spring‑based download library that uses annotations to simplify downloading files, HTTP resources, or custom objects, supports both WebMvc and WebFlux, handles concurrency, compression, and event‑driven logging, and provides a modular architecture for extensibility.
This article introduces Spring AI, a Spring ecosystem module that simplifies building, training, and deploying AI applications for Java developers, covering its background, goals, core components such as data processing, model training, deployment, practical code examples, use cases, advantages, challenges, and future outlook.
This article explains how to refactor the Spring MVC Controller layer by unifying response structures, using ResponseBodyAdvice for automatic wrapping, handling parameter validation with JSR‑303, and implementing custom exceptions with centralized exception handling to simplify and standardize API responses.
