itext PDF转图片

使用iText库将PDF转换为图片（如PNG）的Java示例如下：

1. 引入必要的库:

import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.parser.PdfReaderContentParser;
import com.itextpdf.parser.image.ImageRenderListener;
import java.io.File;
import javax.imageio.ImageIO;

2. 创建PdfReaderContentParser并监听图像:

public class ImageConverter implements ImageRenderListener {
    private File outputDir;

    public void convertPdfToImages(String pdfFilePath, String outputPath) throws Exception {
        PdfReader reader = new PdfReader(pdfFilePath);
        outputDir = new File(outputPath);

        PdfReaderContentParser parser = new PdfReaderContentParser(reader);
        parser.setListener(this); // 设置ImageRenderListener

        for (int i = 1; i <= reader.getNumberOfPages(); i++) {
            parser.processContent(i);
        }

        reader.close();
    }

    @Override
    public void renderImage(ImageRendered image) {
        try {
            String fileName = "page_" + image.getPageNumber() + ".png";
            File outputFile = new File(outputDir, fileName);
            ImageIO.write(image.getImage(), "png", outputFile);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

3. 调用转换方法:

try {
    ImageConverter converter = new ImageConverter();
    converter.convertPdfToImages("/path/to/your/pdf.pdf", "/path/to/output/images");
} catch (Exception e) {
    e.printStackTrace();
}