在工作中，遇到一个需要将pdf转为tif并将图片大小限制到30kb以内的需求。在网上看了一圈，也因为依赖版本等等踩了一些坑，为此记录下来学习的过程。
`import com.github.jaiimageio.impl.plugins.tiff.TIFFImageWriterSpi;
import com.github.jaiimageio.plugins.tiff.BaselineTIFFTagSet;
import com.github.jaiimageio.plugins.tiff.TIFFDirectory;
import com.github.jaiimageio.plugins.tiff.TIFFField;
import com.github.jaiimageio.plugins.tiff.TIFFTag;
import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.rendering.ImageType;
import org.apache.pdfbox.rendering.PDFRenderer;
import javax.imageio.;
import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.stream.ImageOutputStream;
import java.awt.;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
public class TifUtils {
private static Logger logger = Logger.getLogger(TifUtils.class);
public static void main(String[] args) throws FileNotFoundException {
// 初始化 Log4j
BasicConfigurator.configure();
File file = new File("/Users/xu/testpdf/华为OD面试一轮技术面试总结 2022.9.pdf");
FileInputStream fileInputStream = new FileInputStream(file);
String dir = "/Users/xu/testpdf";
pdf2tif(file, new File(dir), 200);
}
public static List pdf2tif(File file1, File dir, int dpi) {
try (PDDocument pdf = PDDocument.load(file1)) {
BufferedImage[] images = new BufferedImage[pdf.getNumberOfPages()];
PDFRenderer pdfRenderer = new PDFRenderer(pdf);
List files = new ArrayList<>();
long suffix = System.currentTimeMillis();
for (int i = 0; i < images.length; i++) {
// PDPage page = (PDPage) pdf.getDocumentCatalog().getAllPages().get(i);
PDPage page1 = pdf.getPage(i);
BufferedImage image;
BufferedImage binaryImage = pdfRenderer.renderImageWithDPI(i, 300, ImageType.BINARY);
// PDFRenderer pdfRenderer = new PDFRenderer(pdf);
// BufferedImage image = pdfRenderer.renderImageWithDPI(i, 300);
// BufferedImage bufferedImage = convertToBinaryImage(image);
images[i] = binaryImage;
File file = new File(dir.getAbsolutePath() + File.separator + suffix + "-" + (i + 1) + ".tiff");
try (FileOutputStream out = new FileOutputStream(file); ImageOutputStream ios = ImageIO.createImageOutputStream(out)) {
TIFFImageWriterSpi tiffWriter = new TIFFImageWriterSpi();
ImageWriter writer = tiffWriter.createWriterInstance();
ImageWriteParam param = writer.getDefaultWriteParam();
param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
param.setCompressionType("CCITT T.6");
param.setCompressionQuality(1);
IIOMetadata metadata = createMetadata(writer, param, 200);
writer.setOutput(ios);
writer.write(metadata, new IIOImage(binaryImage, null, metadata), param);
logger.info("第"+(i+1)+"张图片 convert success");
logger.error("第"+(i+1)+"张图片 convert success");
} catch (IOException e) {
// logger.error(e);;
}
files.add(file);
}
return files;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
private static IIOMetadata createMetadata(ImageWriter writer, ImageWriteParam writerParams, int resolution) throws IIOInvalidTreeException {
// Get default metadata from writer
ImageTypeSpecifier type = writerParams.getDestinationType();
IIOMetadata meta = writer.getDefaultImageMetadata(type, writerParams);
// Convert default metadata to TIFF metadata
TIFFDirectory dir = TIFFDirectory.createFromMetadata(meta);
// Get {X,Y} resolution tags
BaselineTIFFTagSet base = BaselineTIFFTagSet.getInstance();
TIFFTag tagXRes = base.getTag(BaselineTIFFTagSet.TAG_X_RESOLUTION);
TIFFTag tagYRes = base.getTag(BaselineTIFFTagSet.TAG_Y_RESOLUTION);
// Create {X,Y} resolution fields
TIFFField fieldXRes = new TIFFField(tagXRes, TIFFTag.TIFF_RATIONAL, 1, new long[][]{{resolution, 1}});
TIFFField fieldYRes = new TIFFField(tagYRes, TIFFTag.TIFF_RATIONAL, 1, new long[][]{{resolution, 1}});
// Add {X,Y} resolution fields to TIFFDirectory
dir.addTIFFField(fieldXRes);
dir.addTIFFField(fieldYRes);
dir.addTIFFField(new TIFFField(base.getTag(BaselineTIFFTagSet.TAG_RESOLUTION_UNIT), BaselineTIFFTagSet.RESOLUTION_UNIT_CENTIMETER));
// Return TIFF metadata so it can be picked up by the IIOImage
return dir.getAsMetadata();
}`