Java 读取PDF中的文本和图片的方法

import com.spire.pdf.*;import javax.imageio.ImageIO;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileWriter;import java.io.IOException;public class ExtractText {  public static void main(String[]args) throws Exception {    //加载测试文档    PdfDocument pdf = new PdfDocument("sample.pdf");    //实例化StringBuilder类    StringBuilder sb = new StringBuilder();    //定义一个int型变量    int index = 0;    //遍历PDF文档中每页    PdfPageBase page;    for (int i= 0; i<pdf.getPages().getCount();i++) {      page = pdf.getPages().get(i);      //调用extractText()方法提取文本      sb.append(page.extractText(true));      FileWriter writer;      try {        //将StringBuilder对象中的文本写入到txt        writer = new FileWriter("ExtractText.txt");        writer.write(sb.toString());        writer.flush();      } catch (IOException e) {        e.printStackTrace();      }      //调用extractImages方法获取图片      for (BufferedImage image : page.extractImages()) {          //指定输出图片名，指定图片格式          File output = new File(String.format("Image_%d.png", index++));          ImageIO.write(image, "PNG", output);      }    }    pdf.close();  }}