通过Java实现添加或删除PDF中的附件

这里介绍通过Java实现添加或删除PDF中的附件的完整攻略：

1. 添加附件

1.1 引入相关库

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

import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSStream;
import org.apache.pdfbox.io.IOUtils;
import org.apache.pdfbox.pdfparser.PDFParser;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.common.PDStream;
import org.apache.pdfbox.pdmodel.interactive.action.PDActionFactory;
import org.apache.pdfbox.pdmodel.interactive.action.PDActionJavaScript;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationFileAttachment;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageFitWidthDestination;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageXYZDestination;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineItem;

1.2 添加附件的具体实现

public class AddAttachmentInPDF {

    public static void main(String[] args) throws IOException {
        //定义输入和输出文件
        File pdfFile = new File("example.pdf");
        File attachFile = new File("attach.pdf");

        //载入PDF文件
        try (PDDocument document = PDFParser.load(pdfFile)) {
            //创建文件附件
            PDAnnotationFileAttachment fileAttachment = new PDAnnotationFileAttachment();

            //设置文件名和描述
            fileAttachment.setFile("Attachment Name", IOUtils.toByteArray(new FileInputStream(attachFile)));
            fileAttachment.setContents("Attachment Description");

            //设置位置和大小
            fileAttachment.setRectangle(new PDRectangle(50, 50, 100, 100));

            //添加到页面
            document.getPage(0).getAnnotations().add(fileAttachment);

            //创建外部文件附件对象
            PDOutlineItem annotation = new PDOutlineItem();
            annotation.setTitle("Open Document");

            //添加行为和目的地
            PDActionJavaScript js = new PDActionJavaScript("this.exportDataObject({cName: 'Attachment Name', nLaunch: 2});");
            PDActionFactory.createAction(js);
            PDPageXYZDestination dest = new PDPageXYZDestination();
            dest.setPage(document.getPage(0));
            dest.setZoom(1);
            dest.setTop(new Float(0));
            dest.setLeft(new Float(0));
            PDPageFitWidthDestination fit = new PDPageFitWidthDestination();
            fit.setPage(document.getPage(0));
            fit.setTop(new Float(0));

            //设置附件属性
            fileAttachment.setName("Attachment Name");
            fileAttachment.setPage(document.getPage(0));
            fileAttachment.setParent(annotation);
            fileAttachment.setModifiedDate(new Date());
            fileAttachment.setAction(js);
            fileAttachment.setDestination(dest);
            fileAttachment.setFit(fit);

            //保存为新文件
            document.save(new File("example_out.pdf"));
        }
    }
}

1.3 示例

下面是一个添加附件的示例代码：

public class AddAttachmentInPDF {

    public static void main(String[] args) throws IOException {
        //定义输入和输出文件
        File pdfFile = new File("example.pdf");
        File attachFile = new File("attach.pdf");

        //载入PDF文件
        try (PDDocument document = PDFParser.load(pdfFile)) {
            //创建文件附件
            PDAnnotationFileAttachment fileAttachment = new PDAnnotationFileAttachment();

            //设置文件名和描述
            fileAttachment.setFile("Attachment Name", IOUtils.toByteArray(new FileInputStream(attachFile)));
            fileAttachment.setContents("Attachment Description");

            //设置位置和大小
            fileAttachment.setRectangle(new PDRectangle(50, 50, 100, 100));

            //添加到页面
            document.getPage(0).getAnnotations().add(fileAttachment);

            //保存为新文件
            document.save(new File("example_out.pdf"));
        }
    }
}

2. 删除附件

2.1 引入相关库

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSStream;
import org.apache.pdfbox.pdfparser.PDFParser;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.common.PDStream;
import org.apache.pdfbox.pdmodel.interactive.action.PDActionFactory;
import org.apache.pdfbox.pdmodel.interactive.action.PDActionJavaScript;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationFileAttachment;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageFitWidthDestination;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageXYZDestination;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineItem;

2.2 删除附件的具体实现

public class DeleteAttachmentInPDF {

    public static void main(String[] args) throws IOException {
        //定义输入和输出文件
        File pdfFile = new File("example.pdf");

        //载入PDF文件
        try (PDDocument document = PDFParser.load(pdfFile)) {
            //获取第一页上的所有注释
            List<PDAnnotation> annotations = document.getPage(0).getAnnotations();

            //遍历注释
            for (PDAnnotation annotation : annotations) {
                if (annotation instanceof PDAnnotationFileAttachment) {
                    //获取附件字典
                    COSDictionary fileAttachmentDict = ((PDAnnotationFileAttachment) annotation).getCOSObject();

                    //获取附件字典中的Filespec中的Stream字典
                    COSDictionary fileSpecDict = fileAttachmentDict.getCOSDictionary(COSName.FS);

                    if (fileSpecDict != null) {
                        COSDictionary fileStreamDict = fileSpecDict.getCOSDictionary(COSName.EF);

                        //删除字典中的Stream字典
                        if (fileStreamDict != null) {
                            COSStream cosStream = (COSStream) PDStream.createFromCOS(fileStreamDict);
                            document.getDocument().getObjects().remove(cosStream.getCOSObject());
                        }
                    }

                    //删除注释
                    document.getPage(0).getAnnotations().remove(annotation);
                }
            }

            //保存为新文件
            document.save(new File("example_out.pdf"));
        }
    }
}

2.3 示例

下面是一个删除附件的示例代码：

public class DeleteAttachmentInPDF {

    public static void main(String[] args) throws IOException {
        //定义输入和输出文件
        File pdfFile = new File("example.pdf");

        //载入PDF文件
        try (PDDocument document = PDFParser.load(pdfFile)) {
            //获取第一页上的所有注释
            List<PDAnnotation> annotations = document.getPage(0).getAnnotations();

            //遍历注释
            for (PDAnnotation annotation : annotations) {
                if (annotation instanceof PDAnnotationFileAttachment) {
                    //获取附件字典
                    COSDictionary fileAttachmentDict = ((PDAnnotationFileAttachment) annotation).getCOSObject();

                    //获取附件字典中的Filespec中的Stream字典
                    COSDictionary fileSpecDict = fileAttachmentDict.getCOSDictionary(COSName.FS);

                    if (fileSpecDict != null) {
                        COSDictionary fileStreamDict = fileSpecDict.getCOSDictionary(COSName.EF);

                        //删除字典中的Stream字典
                        if (fileStreamDict != null) {
                            COSStream cosStream = (COSStream) PDStream.createFromCOS(fileStreamDict);
                            document.getDocument().getObjects().remove(cosStream.getCOSObject());
                        }
                    }

                    //删除注释
                    document.getPage(0).getAnnotations().remove(annotation);
                }
            }

            //保存为新文件
            document.save(new File("example_out.pdf"));
        }
    }
}

以上就是通过Java实现添加或删除PDF中的附件的完整攻略。