Data Export in Spring Boot refers to the process of extracting application data—typically retrieved from databases or business services—and transforming it into downloadable, portable file formats for offline analysis, archiving, or reporting. By combining Spring MVC’s streaming and response handling with specialized Java document libraries, applications can generate structured files on demand and serve them directly to end users over HTTP.
1. CSV Export and Excel Export
CSV and Excel exports handle tabular datasets intended for numerical analysis, reporting, and manipulation in spreadsheet applications.
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CSV Export:
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Uses lightweight libraries (such as Apache Commons CSV or OpenCSV) or plain
PrintWriterstreams to write comma-separated text data. -
Ideal for large datasets because of its low memory overhead and simple plaintext structure.
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Configured with
Content-Type: text/csvand served viaContent-Disposition: attachment; filename="report.csv".
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Excel Export (.xlsx):
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Typically implemented using Apache POI (e.g.,
XSSFWorkbookor memory-optimizedSXSSFWorkbookfor large volumes). -
Supports rich workbook features, including multiple sheets, custom cell styling, data formatting, formulas, and auto-sized column widths.
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Configured with
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.
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2. PDF Export
PDF export generates read-only, layout-precise documents suitable for printing, invoicing, receipts, and official documentation.
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Common Libraries: Built using popular Java document rendering tools such as iText / OpenPDF, Apache PDFBox, or HTML-to-PDF converters (like Flying Saucer or wkhtmltopdf paired with template engines such as Thymeleaf).
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Layout and Design: Enables precise visual structure, including page numbering, custom fonts, vector graphics, embedded company logos, and styled tabular data.
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HTTP Delivery: Streamed directly to the client via
HttpServletResponseor as aResponseEntity<byte[]>/ResponseEntity<Resource>withContent-Type: application/pdf. -
Display Options: Can be delivered as an attachment for immediate local saving or set to
inlinedisposition to allow previewing directly within the client browser.