This article demonstrates how to securely implement file upload, download, and preview in a SpringBoot application using MinIO, token validation, and base64‑encoded URLs, while also providing complete code snippets and practical usage notes for backend developers.
The Concept‑Download library lets SpringBoot developers replace verbose download code with a single @Download annotation that automatically handles classpath resources, local files, HTTP URLs, custom objects, compression and reactive streaming, simplifying batch and QR‑code ZIP exports.
The article describes a production OOM incident caused by downloading a 2.4 GB file, walks through GC log and heap‑dump analysis using MAT, identifies the problematic use of FileUtils.readFileToByteArray, and presents streaming and external storage solutions to prevent memory exhaustion.
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 explains how HttpServletResponse represents server responses in Java web applications, covering methods for sending data, headers, and status codes, demonstrates outputting Chinese characters via OutputStream and PrintWriter, shows numeric output handling, and provides detailed examples of file download implementations with proper encoding considerations.
