Mengekstrak lampiran dari PDF

Aspose.PDF for Java mendukung beberapa alur ekstraksi tergantung pada cara lampiran disimpan dalam dokumen.

Mengekstrak satu lampiran berdasarkan nama

Gunakan contoh ini ketika Anda perlu menyimpan satu file tersemat tertentu dari sebuah PDF.

1. Buka PDF sumber Document.
2. Iterasikan melalui koleksi file tersemat hingga nama lampiran yang diperlukan ditemukan.
3. Salin aliran lampiran ke file output dan berhenti setelah ekstraksi.

public static void extractSingleAttachment(Path inputFile, String attachmentName, Path outputFile) throws Exception {
    try (Document document = new Document(inputFile.toString())) {
        System.out.println("Extracting attachment: " + attachmentName);

        boolean attachmentFound = false;
        for (FileSpecification fileSpecification : document.getEmbeddedFiles()) {
            if (attachmentName.equals(fileSpecification.getName())) {
                try (InputStream inputStream = fileSpecification.getContents();
                     OutputStream outputStream = Files.newOutputStream(outputFile)) {
                    inputStream.transferTo(outputStream);
                }
                System.out.println("Attachment extracted successfully");
                attachmentFound = true;
                break;
            }
        }

        if (!attachmentFound) {
            throw new IllegalArgumentException("Attachment '" + attachmentName + "' not found in PDF");
        }
    }
}

Mencetak parameter file tersemat

Metode pembantu ini mencetak metadata yang disimpan dalam sebuah objek FileParams.

1. Periksa apakah objek parameter file ada.
2. Baca nilai checksum, tanggal pembuatan, tanggal modifikasi, dan ukuran yang tersedia.
3. Cetak nilai-nilai tersebut ke konsol.

public static void printFileParams(FileParams params) {
    if (params != null) {
        try {
            System.out.println("CheckSum: " + params.getCheckSum());
        } catch (Exception ex) {
            System.out.println("CheckSum: null");
        }
        System.out.println("Creation Date: " + params.getCreationDate());
        System.out.println("Modification Date: " + params.getModDate());
        System.out.println("Size: " + params.getSize());
    }
}

Mengekstrak semua lampiran tersemat

Gunakan contoh ini ketika setiap file tersemat dalam PDF harus ditulis ke direktori output.

1. Buka PDF sumber Document.
2. Iterasikan koleksi file tersemat dan tentukan nama file output yang aman untuk setiap item.
3. Cetak metadata, simpan setiap aliran lampiran, dan lanjutkan hingga semua file diekspor.

public static void extractAttachments(Path inputFile, Path outputDir) throws Exception {
    try (Document document = new Document(inputFile.toString())) {
        System.out.println("Total files: " + document.getEmbeddedFiles().size());

        int fileIndex = 1;
        for (FileSpecification fileSpecification : document.getEmbeddedFiles()) {
            String fileName = fileSpecification.getName();
            if (fileName == null || fileName.isBlank()) {
                fileName = fileSpecification.getUnicodeName();
            }
            if (fileName == null || fileName.isBlank()) {
                fileName = "attachment_" + fileIndex + ".bin";
            }

            System.out.println("Name: " + fileName);
            System.out.println("Description: " + fileSpecification.getDescription());
            System.out.println("Mime Type: " + fileSpecification.getMIMEType());
            printFileParams(fileSpecification.getParams());

            Path outputPath = outputDir.resolve(fileName);
            try (InputStream inputStream = fileSpecification.getContents();
                 OutputStream outputStream = Files.newOutputStream(outputPath)) {
                inputStream.transferTo(outputStream);
            }
            fileIndex++;
        }
    }
}

Mengekstrak anotasi lampiran file

Gunakan contoh ini ketika file dilampirkan melalui anotasi halaman bukan hanya melalui koleksi file tersemat.

1. Buka PDF sumber Document.
2. Temukan yang pertama FileAttachmentAnnotation di halaman.
3. Baca spesifikasi file-nya, ekspor isinya, dan cetak jalur tujuan.

public static void extractFileAttachmentAnnotation(Path inputFile, Path outputDir) throws Exception {
    try (Document document = new Document(inputFile.toString())) {
        FileAttachmentAnnotation fileAttachment = null;
        for (Annotation annotation : document.getPages().get_Item(1).getAnnotations()) {
            if (annotation.getAnnotationType() == AnnotationType.FileAttachment) {
                fileAttachment = (FileAttachmentAnnotation) annotation;
                break;
            }
        }

        if (fileAttachment == null) {
            System.out.println("File attachment annotation not found.");
            return;
        }

        FileSpecification fileSpecification = fileAttachment.getFile();
        System.out.println("File name: " + fileSpecification.getName());

        Path outputPath = outputDir.resolve("extracted-" + fileSpecification.getName());
        try (InputStream inputStream = fileSpecification.getContents();
             OutputStream outputStream = Files.newOutputStream(outputPath)) {
            inputStream.transferTo(outputStream);
        }

        System.out.println("Extracted to: " + outputPath);
    }
}