java pdf 压缩

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itext7-core</artifactId>
    <version>7.1.16</version>
</dependency>

import com.itextpdf.kernel.pdf.*;
import com.itextpdf.kernel.pdf.compression.CompressionConstants;

import java.io.*;

public class PdfCompressor {

    public static void main(String[] args) throws IOException {
        String inputPath = "input.pdf";
        String outputPath = "compressed.pdf";

        PdfReader reader = new PdfReader(inputPath);
        PdfWriter writer = new PdfWriter(outputPath, new WriterProperties().setFullCompressionMode(true));

        PdfDocument pdfDocument = new PdfDocument(reader, writer);
        pdfDocument.processOutlineTree();
        pdfDocument.close();
    }
}

<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.24</version>
</dependency>

import org.apache.pdfbox.io.MemoryUsageSetting;
import org.apache.pdfbox.pdmodel.PDDocument;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class PdfCompressor {

    public static void main(String[] args) throws IOException {
        String inputPath = "input.pdf";
        String outputPath = "compressed.pdf";

        try (FileInputStream fis = new FileInputStream(inputPath);
             PDDocument document = PDDocument.load(fis, MemoryUsageSetting.setupTempFileOnly())) {

            document.save(outputPath, MemoryUsageSetting.setupTempFileOnly());
        }
    }
}