📌  相关文章
📜  PDFBox-文档属性

📅  最后修改于: 2020-11-12 05:15:14             🧑  作者: Mango

与其他文件一样，PDF文档也具有文档属性。这些属性是键值对。每个属性都提供有关文档的特定信息。

以下是PDF文档的属性-

S.No. Property & Description
1

File

This property holds the name of the file.
2

Title

Using this property, you can set the title for the document.
3

Author

Using this property, you can set the name of the author for the document.
4

Subject

Using this property, you can specify the subject of the PDF document.
5

Keywords

Using this property, you can list the keywords with which we can search the document.
6

Created

Using this property, you can set the date created for the document.
7

Modified

Using this property, you can set the date modified for the document.
8

Application

Using this property, you can set the Application of the document.

以下是PDF文档的文档属性表的屏幕截图。

PDF属性

设定文件属性

PDFBox为您提供了一个名为PDDocumentInformation的类。此类具有一组setter和getter方法。

此类的setter方法用于将值设置为文档的各种属性，而getter方法用于获取这些值。

以下是PDDocumentInformation类的setter方法。

S.No. Method & Description
1

setAuthor(String author)

This method is used to set the value for the property of the PDF document named Author.
2

setTitle(String title)

This method is used to set the value for the property of the PDF document named Title.
3

setCreator(String creator)

This method is used to set the value for the property of the PDF document named Creator.
4

setSubject(String subject)

This method is used to set the value for the property of the PDF document named Subject.
5

setCreationDate(Calendar date)

This method is used to set the value for the property of the PDF document named CreationDate.
6

setModificationDate(Calendar date)

This method is used to set the value for the property of the PDF document named ModificationDate.
7

setKeywords(String keywords list)

This method is used to set the value for the property of the PDF document named Keywords.

例

PDFBox提供了一个称为PDDocumentInformation的类，该类提供了各种方法。这些方法可以为文档设置各种属性并检索它们。

本示例演示如何向PDF文档添加诸如Author，Title，Date和Subject之类的属性。在这里，我们将创建一个名为doc_attributes.pdf的PDF文档，向其中添加各种属性，并将其保存在路径C：/ PdfBox_Examples /中。将此代码保存在名为AddingAttributes.java的文件中。

import java.io.IOException; 
import java.util.Calendar; 
import java.util.GregorianCalendar;
  
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentInformation;
import org.apache.pdfbox.pdmodel.PDPage;

public class AddingDocumentAttributes {
   public static void main(String args[]) throws IOException {

      //Creating PDF document object
      PDDocument document = new PDDocument();

      //Creating a blank page
      PDPage blankPage = new PDPage();
       
      //Adding the blank page to the document
      document.addPage( blankPage );

      //Creating the PDDocumentInformation object 
      PDDocumentInformation pdd = document.getDocumentInformation();

      //Setting the author of the document
      pdd.setAuthor("Tutorialspoint");
       
      // Setting the title of the document
      pdd.setTitle("Sample document"); 
       
      //Setting the creator of the document 
      pdd.setCreator("PDF Examples"); 
       
      //Setting the subject of the document 
      pdd.setSubject("Example document"); 
       
      //Setting the created date of the document 
      Calendar date = new GregorianCalendar();
      date.set(2015, 11, 5); 
      pdd.setCreationDate(date);
      //Setting the modified date of the document 
      date.set(2016, 6, 5); 
      pdd.setModificationDate(date); 
       
      //Setting keywords for the document 
      pdd.setKeywords("sample, first example, my pdf"); 
 
      //Saving the document 
      document.save("C:/PdfBox_Examples/doc_attributes.pdf");

      System.out.println("Properties added successfully ");
       
      //Closing the document
      document.close();

   }
}

使用以下命令从命令提示符处编译并执行保存的Java文件。

javac AddingAttributes.java 
java AddingAttributes

执行后，上述程序将所有指定的属性添加到显示以下消息的文档中。

Properties added successfully

现在，如果您访问给定的路径，则可以找到在其中创建的PDF。右键单击文档，然后选择文档属性选项，如下所示。

文件属性

这将为您提供文档属性窗口，您可以在此处观察文档的所有属性均设置为指定值。

属性菜单

检索文档属性

您可以使用PDDocumentInformation类提供的getter方法来检索文档的属性。

以下是PDDocumentInformation类的getter方法。

S.No. Method & Description
1

getAuthor()

This method is used to retrieve the value for the property of the PDF document named Author.
2

getTitle()

This method is used to retrieve the value for the property of the PDF document named Title.
3

getCreator()

This method is used to retrieve the value for the property of the PDF document named Creator.
4

getSubject()

This method is used to retrieve the value for the property of the PDF document named Subject.
5

getCreationDate()

This method is used to retrieve the value for the property of the PDF document named CreationDate.
6

getModificationDate()

This method is used to retrieve the value for the property of the PDF document named ModificationDate.
7

getKeywords()

This method is used to retrieve the value for the property of the PDF document named Keywords.

例

本示例演示了如何检索现有PDF文档的属性。在这里，我们将创建一个Java程序并加载名为doc_attributes.pdf的PDF文档，该文档保存在路径C：/ PdfBox_Examples /中，并检索其属性。将此代码保存在名为RetrivingDocumentAttributes.java的文件中。

import java.io.File; 
import java.io.IOException;

import org.apache.pdfbox.pdmodel.PDDocument; 
import org.apache.pdfbox.pdmodel.PDDocumentInformation;

public class RetrivingDocumentAttributes {
   public static void main(String args[]) throws IOException {
      
      //Loading an existing document 
      File file = new File("C:/PdfBox_Examples/doc_attributes.pdf")
      PDDocument document = PDDocument.load(file);
      //Getting the PDDocumentInformation object
      PDDocumentInformation pdd = document.getDocumentInformation();

      //Retrieving the info of a PDF document
      System.out.println("Author of the document is :"+ pdd.getAuthor());
      System.out.println("Title of the document is :"+ pdd.getTitle());
      System.out.println("Subject of the document is :"+ pdd.getSubject());

      System.out.println("Creator of the document is :"+ pdd.getCreator());
      System.out.println("Creation date of the document is :"+ pdd.getCreationDate());
      System.out.println("Modification date of the document is :"+ 
         pdd.getModificationDate()); 
      System.out.println("Keywords of the document are :"+ pdd.getKeywords()); 
       
      //Closing the document 
      document.close();        
   }  
}

使用以下命令从命令提示符处编译并执行保存的Java文件。

javac RetrivingDocumentAttributes.java 
java RetrivingDocumentAttributes

执行后，上述程序将检索文档的所有属性并显示它们，如下所示。

Author of the document is :Tutorialspoint 
Title of the document is :Sample document 
Subject of the document is :Example document 
Creator of the document is :PDF Examples 
Creation date of the document is :11/5/2015
Modification date of the document is :6/5/2016
Keywords of the document are :sample, first example, my pdf