最近，想着将pdf的文件进行读取其内容，发现了一个比较好用的依赖pdfbox。目前使用这个依赖，进行实现一个简单实例，如果之后需要使用到更深的了解，会进行更新。这里提醒一下：jdk8尽量采用pdfbox3.x版本。

1. 对于文件的读取

File file = new File("E:\\关于pdfbox学习.pdf");
 PDDocument document = Loader.loadPDF(file);
 //Instantiate PDFTextStripper class
 PDFTextStripper pdfStripper = new PDFTextStripper();
 //Retrieving text from PDF document
 String text = pdfStripper.getText(document);
 System.out.println(text);

通过这个代码可以读取到相应的pdf文字:

上述是关于文字的读取，如果是获取pdf中的截图，那么进行如下操作：

2. 获取pdf中的截图
   代码展示：

int pageNum = document.getNumberOfPages();
for (int i = 0; i < pageNum; i++) {
    PDPage page = document.getPage(i);
    PDResources resources = page.getResources();
    Iterable<COSName> xObjectNames = resources.getXObjectNames();
    if (xObjectNames != null){
        Iterator<COSName> names = xObjectNames.iterator();
        while (names.hasNext()){
            COSName next = names.next();
            if (resources.isImageXObject(next)){
                PDImageXObject xObject = (PDImageXObject) resources.getXObject(next);
                BufferedImage image = xObject.getImage();
                ImageIO.write(image, "png", new File("E:\\" + i + ".png"));
            }
        }
    }
}

结果如下：

所有代码展示：

package com.example.demo;

import org.apache.pdfbox.Loader;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.graphics.PDXObject;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.text.PDFTextStripper;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
public class FoxApiMain {
    public static void main(String[] args) {  //

        try{
            //读取本地文件
            File file = new File("E:\\关于pdfbox学习.pdf");
            PDDocument document = Loader.loadPDF(file);
            //Instantiate PDFTextStripper class
            PDFTextStripper pdfStripper = new PDFTextStripper();
            //Retrieving text from PDF document
            String text = pdfStripper.getText(document);
            System.out.println(text);

            int pageNum = document.getNumberOfPages();
            for (int i = 0; i < pageNum; i++) {
                PDPage page = document.getPage(i);
                PDResources resources = page.getResources();
                Iterable<COSName> xObjectNames = resources.getXObjectNames();
                if (xObjectNames != null){
                    Iterator<COSName> names = xObjectNames.iterator();
                    while (names.hasNext()){
                        COSName next = names.next();
                        if (resources.isImageXObject(next)){
                            PDImageXObject xObject = (PDImageXObject) resources.getXObject(next);
                            BufferedImage image = xObject.getImage();
                            ImageIO.write(image, "png", new File("E:\\" + i + ".png"));

                        }
                    }
                }
            }

            document.close();

        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }
}