How to Set Up kkFileView for Instant File Preview with Docker and SpringBoot

In a previous article we used MinIO for object storage; now we introduce kkFileView, a SpringBoot‑based service that enables online preview of various file formats.

kkFileView Overview

kkFileView is an open‑source file preview solution (5.7k+ stars on GitHub) built with SpringBoot, supporting documents like docx, xlsx, pptx, pdf, txt, zip, images, video, audio, etc.

Installation

Windows

Download the latest release package from the official repository.

Extract it to a directory and run startup.bat in the bin folder.

To modify configuration, edit the application.properties file under the config directory.

Linux

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

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

Access the test page at http://<your_ip>:8012.

Usage

After storing files in MinIO (e.g., in a bucket named preview), obtain the file URL, base64‑encode it, and call the preview endpoint:

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

Examples include previewing images, Word documents (converted to PDF or JPG), PPT, PDF, Excel, Markdown, and compressed files.

Configuration

Configuration files reside in the config directory. To edit them from a Docker container:

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

Mount the configuration, 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 the watermark.txt property in application.properties:

# Watermark content
# To disable, set empty: watermark.txt = ${WATERMARK_TXT:}
watermark.txt = ${WATERMARK_TXT:macrozheng}

Summary

kkFileView provides a simple way to preview Office documents, images, videos, and more; it converts Word and PPT files to PDF or JPG for display, making it a versatile solution for building an all‑in‑one online file preview service.