PDF文档生成首页缩略图

1. 导包

<!-- PDF转图片 -->
<dependency>
    <groupId>org.icepdf.os</groupId>
    <artifactId>icepdf-core</artifactId>
    <version>6.2.2</version>
    <exclusions>
        <exclusion>
            <groupId>javax.media</groupId>
            <artifactId>jai_core</artifactId>
        </exclusion>
    </exclusions>
</dependency>

排除 jai_core 是因为在导入包时会报错：jai_core missing，直接排除即可。

import org.icepdf.core.pobjects.Document;
import org.icepdf.core.pobjects.Page;
import org.icepdf.core.util.GraphicsRenderingHints;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.util.Iterator;

/**
 * 截取PDF文档第一页生成缩略图
 */
public class CapturePdfFirstPageThumbnailUtil {

    /**
     * 生成缩略图
     *
     * @param inputFile  需要生成缩略图的PDF文件路径
     * @param outputFile 生成缩略图的存储路径
     */
    public static void generateThumbnail(String inputFile, String outputFile) {
        long start = System.currentTimeMillis();
        Document document;
        try {
            float rotation = 0f;
            // 缩略图显示倍数，1表示不缩放，0.5表示缩小到50%
            float zoom = 0.5f;

            document = new Document();
            document.setFile(inputFile);

            BufferedImage image = (BufferedImage) document.getPageImage(0,
                    GraphicsRenderingHints.SCREEN,
                    Page.BOUNDARY_CROPBOX, rotation, zoom);

            Iterator<ImageWriter> iter = ImageIO.getImageWritersBySuffix("jpg");
            ImageWriter writer = iter.next();

            FileOutputStream out = new FileOutputStream(outputFile);
            ImageOutputStream outImage = ImageIO.createImageOutputStream(out);

            writer.setOutput(outImage);
            writer.write(new IIOImage(image, null, null));

            System.out.println("耗时:" + (System.currentTimeMillis() - start) + "ms");

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        String inputFilePath = "C:\\test.pdf";
        String outputFilePath = "C:\\test.jpg";
        generateThumbnail(inputFilePath, outputFilePath);
    }
}

警告信息不用管，好像是因为用的不是PRO版本吧！

看了一下还挺耗时的。