PDFBox如何从另一个pdf导入acrofield

import java.io.File;
import java.io.IOException;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
import org.apache.pdfbox.pdmodel.interactive.form.PDField;

public class PDFBoxExample {
    public static void main(String[] args) {
        try {
            // 加载源PDF文件
            PDDocument sourceDocument = PDDocument.load(new File("source.pdf"));

            // 获取源PDF文件的acrofield
            PDAcroForm sourceAcroForm = sourceDocument.getDocumentCatalog().getAcroForm();
            PDField[] sourceFields = sourceAcroForm.getFields();

            // 创建目标PDF文件
            PDDocument targetDocument = new PDDocument();
            PDPage targetPage = new PDPage();
            targetDocument.addPage(targetPage);

            // 导入acrofield到目标PDF文件
            PDAcroForm targetAcroForm = targetDocument.getDocumentCatalog().getAcroForm();
            for (PDField sourceField : sourceFields) {
                targetAcroForm.getFields().add(sourceField);
            }

            // 保存目标PDF文件
            targetDocument.save("target.pdf");
            targetDocument.close();
            sourceDocument.close();

            System.out.println("acrofield导入成功！");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}