JavaFX应用中显示PDF的可行方案咨询（多种尝试遇阻）

Hey Steve, I totally get how frustrating it can be to hunt for a PDF display solution that checks all your boxes—no Swing hacks, no messy resource folder workarounds, no pricey libraries. Let’s walk through some practical, Maven-friendly options that fit your needs:

1. Apache PDFBox + JavaFX Canvas #

Apache PDFBox is a rock-solid open-source PDF processing library that integrates smoothly with Maven, and we can use it to render PDF pages directly to a JavaFX Canvas (no Swing components cluttering your UI).

Step 1: Add Maven Dependency #

Drop this into your pom.xml to pull in PDFBox:

<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.32</version> <!-- Use the latest stable version available -->
</dependency>

Step 2: Basic Rendering Code #

Here’s a quick example to load a PDF and render its first page to a JavaFX Canvas:

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.PDFRenderer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.image.WritableImage;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.embed.swing.SwingFXUtils;
import java.io.File;

public class PDFCanvasViewer extends Application {
    @Override
    public void start(Stage stage) throws Exception {
        File targetPDF = new File("your-document-path.pdf");
        try (PDDocument document = PDDocument.load(targetPDF)) {
            PDFRenderer renderer = new PDFRenderer(document);
            // Render first page to a BufferedImage
            java.awt.image.BufferedImage awtImage = renderer.renderImage(0);
            
            // Convert to JavaFX-compatible image
            WritableImage fxImage = SwingFXUtils.toFXImage(awtImage, null);
            
            // Draw image to Canvas
            Canvas canvas = new Canvas(fxImage.getWidth(), fxImage.getHeight());
            GraphicsContext gc = canvas.getGraphicsContext2D();
            gc.drawImage(fxImage, 0, 0);
            
            StackPane root = new StackPane(canvas);
            Scene scene = new Scene(root, fxImage.getWidth(), fxImage.getHeight());
            stage.setScene(scene);
            stage.show();
        }
    }

    public static void main(String[] args) {
        launch(args);
    }
}

Note: We only use SwingFXUtils for image conversion—no Swing UI components appear in your final JavaFX app.

2. WebView + PDF.js via WebJars (Maven-Managed) #

You mentioned PDF.js felt off-limits because you didn’t want to manually add it to your resources folder—but WebJars solves that! WebJars packages front-end libraries into Maven artifacts, so you can pull PDF.js directly through your build file and access it from the classpath.

Step 1: Add WebJars Dependency #

Add these lines to your pom.xml:

<dependency>
    <groupId>org.webjars</groupId>
    <artifactId>pdfjs</artifactId>
    <version>3.11.174</version> <!-- Grab the latest stable version -->
</dependency>

Step 2: Load PDF.js in WebView #

Instead of a local HTML file, we’ll build the viewer HTML dynamically and point to the WebJars-hosted PDF.js files:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class PDFJSWebViewViewer extends Application {
    @Override
    public void start(Stage stage) {
        WebView webView = new WebView();
        WebEngine webEngine = webView.getEngine();
        
        // Get paths to PDF.js files from WebJars classpath
        String pdfJsCore = getClass().getResource("/META-INF/resources/webjars/pdfjs/3.11.174/build/pdf.js").toExternalForm();
        String pdfJsWorker = getClass().getResource("/META-INF/resources/webjars/pdfjs/3.11.174/build/pdf.worker.js").toExternalForm();
        
        // Dynamic HTML to render the PDF
        String viewerHtml = String.format("""
            <!DOCTYPE html>
            <html>
            <head>
                <meta charset="UTF-8">
                <style>body { margin: 0; } #viewer { width: 100vw; height: 100vh; }</style>
            </head>
            <body>
                <div id="viewer"></div>
                <script>
                    pdfjsLib.GlobalWorkerOptions.workerSrc = '%s';
                    async function loadPDF() {
                        const pdfDoc = await pdfjsLib.getDocument('your-document-path.pdf').promise;
                        const firstPage = await pdfDoc.getPage(1);
                        const viewport = firstPage.getViewport({ scale: 1.2 });
                        const canvas = document.createElement('canvas');
                        const ctx = canvas.getContext('2d');
                        canvas.width = viewport.width;
                        canvas.height = viewport.height;
                        document.getElementById('viewer').appendChild(canvas);
                        await firstPage.render({ canvasContext: ctx, viewport: viewport }).promise;
                    }
                    loadPDF();
                </script>
                <script src="%s"></script>
            </body>
            </html>
            """, pdfJsWorker, pdfJsCore);
        
        webEngine.loadContent(viewerHtml);
        
        Scene scene = new Scene(webView, 800, 600);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

All PDF.js files are managed by Maven—no manual resource folder setup required.

3. iText 7 + JavaFX (AGPL License) #

If you’re comfortable with the AGPL license (make sure to adhere to its terms for distributed apps), iText 7 offers powerful PDF parsing tools. You can use it to convert PDF pages to images and display them in JavaFX ImageView or Canvas, similar to the PDFBox approach.

Maven Dependency #

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>7.2.5</version> <!-- Latest stable version -->
</dependency>

内容的提问来源于stack exchange，提问作者Steve2Fish