How to Build a Powerful File Preview Service with kkFileView and SpringBoot

kkFileView Overview

kkFileView is an open‑source SpringBoot application (over 5.7k stars on GitHub) that provides online preview for common office documents such as DOCX, XLSX, PPTX, PDF, TXT, ZIP, images, videos, and audio files.

Installation

Windows

Download the latest release package from the official repository.

Extract it to a directory and run bin/startup.bat to start the service.

To modify configuration, edit config/application.properties inside the project.

Linux (Docker)

Pull the Docker image: docker pull keking/kkfileview Run the container on port 8012:

docker run -p 8012:8012 --name kkfileview \
-d keking/kkfileview

Usage with MinIO

Store files in a MinIO bucket (e.g., preview) using a client such as S3 Browser, then set the bucket policy to allow anonymous access.

To preview a file, call the online preview endpoint with a base64‑encoded file URL:

http://<span>$host</span>:8012/onlinePreview?url=base64Encode($url)

Examples include previewing images, Word documents (converted to PDF or JPG), PPT files, PDFs, Excel sheets, Markdown text, and ZIP archives.

Configuration

The main configuration resides in config/application.properties. To customize Docker settings, copy the config directory from the container:

docker cp kkfileview:/opt/kkFileView-3.5.1/config /mydata/kkFileView/config

Then mount the config, file, and log directories when running the container:

docker run -p 8012:8012 --name kkfileview \
-v /mydata/kkFileView/config:/opt/kkFileView-3.5.1/config \
-v /mydata/kkFileView/file:/opt/kkFileView-3.5.1/file \
-v /mydata/kkFileView/log:/opt/kkFileView-3.5.1/log \
-d keking/kkfileview

To add a watermark, set watermark.txt=${WATERMARK_TXT:macrozheng} in the properties file.

Summary

kkFileView provides a simple, out‑of‑the‑box solution for online preview of office documents, images, videos, and archives. By converting files to PDF or JPG, it meets most preview needs without complex setup, making it ideal for building a universal file preview service.

Reference

Official documentation: https://kkfileview.keking.cn/zh-cn/index.html