引入所需依赖，注意poi版本，新版本不支持，最好使用和我一样的版本。

<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
   <groupId>org.apache.poi</groupId>
   <artifactId>poi</artifactId>
   <version>3.10-FINAL</version>
</dependency>
<dependency>
   <groupId>org.apache.poi</groupId>
   <artifactId>poi-ooxml</artifactId>
   <version>3.10-FINAL</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml-schemas -->
<dependency>
   <groupId>org.apache.poi</groupId>
   <artifactId>poi-ooxml-schemas</artifactId>
   <version>3.10-FINAL</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-scratchpad -->
<dependency>
   <groupId>org.apache.poi</groupId>
   <artifactId>poi-scratchpad</artifactId>
   <version>3.10-FINAL</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.github.virtuald/curvesapi -->
<dependency>
   <groupId>com.github.virtuald</groupId>
   <artifactId>curvesapi</artifactId>
   <version>1.06</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.xmlbeans/xmlbeans -->
<dependency>
   <groupId>org.apache.xmlbeans</groupId>
   <artifactId>xmlbeans</artifactId>
   <version>3.1.0</version>
</dependency>

调用方式：
   参数fileformat：文件名后缀，例ppt、pptx
   参数str：文件绝对路径
 

   public static void saveYulanFile(String fileformat,String str) throws Exception {
        if(fileformat.equals("ppt") || fileformat.equals("pptx")){
            PptToImage.createPPTImage(new FileInputStream(new File(str)),str.substring(0,str.indexOf("."))+"/");
        }
  }

import org.apache.poi.POIXMLDocument;
import org.apache.poi.hslf.model.Slide;
import org.apache.poi.hslf.model.TextRun;
import org.apache.poi.hslf.usermodel.RichTextRun;
import org.apache.poi.hslf.usermodel.SlideShow;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.xslf.usermodel.XMLSlideShow;
import org.apache.poi.xslf.usermodel.XSLFSlide;
import org.openxmlformats.schemas.drawingml.x2006.main.*;
import org.openxmlformats.schemas.presentationml.x2006.main.CTGroupShape;
import org.openxmlformats.schemas.presentationml.x2006.main.CTShape;
import org.openxmlformats.schemas.presentationml.x2006.main.CTSlide;
import java.awt.*;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.*;

/**
 * @author ：llf
 * @date ：Created in 2020-04-09 11:56
 * @description：${description}
 * @version: v1.0
 */
public class PptToImage {

    public static void create2007PPTImage(InputStream in,String fileOutPath){
        try {
            XMLSlideShow xmlSlideShow=new XMLSlideShow(in);
            Dimension pgsize = xmlSlideShow.getPageSize();
            XSLFSlide[] slides = xmlSlideShow.getSlides();
            FileOutputStream out = null;
            for (int i = 0;i < slides.length;i++){
                CTSlide rawSlide=slides[i].getXmlObject();
                CTGroupShape gs = rawSlide.getCSld().getSpTree();
                CTShape[] shapes = gs.getSpArray();
                for (CTShape shape : shapes) {
                    CTTextBody tb = shape.getTxBody();
                    if (null == tb)
                        continue;
                    CTTextParagraph[] paras = tb.getPArray();
                    CTTextFont font=CTTextFont.Factory.parse(
                            "<xml-fragment xmlns:a=\"http://schemas.openxmlformats.org/drawingml/2006/main\" xmlns:r=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships\" xmlns:p=\"http://schemas.openxmlformats.org/presentationml/2006/main\">"+
                                    "<a:rPr lang=\"zh-CN\" altLang=\"en-US\" dirty=\"0\" smtClean=\"0\"> "+
                                    "<a:latin typeface=\"+mj-ea\"/> "+
                                    "</a:rPr>"+
                                    "</xml-fragment>");
                    for (CTTextParagraph textParagraph : paras) {
                        CTRegularTextRun[] textRuns = textParagraph.getRArray();
                        for (CTRegularTextRun textRun : textRuns) {
                            CTTextCharacterProperties properties=textRun.getRPr();
                            properties.setLatin(font);
                        }
                    }
                }
                BufferedImage img=new BufferedImage(pgsize.width,pgsize.height, BufferedImage.TYPE_INT_RGB);
                Graphics2D graphics=img.createGraphics();
                graphics.setPaint(Color.WHITE);
                graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width,pgsize.height));
                slides[i].draw(graphics);
                out = new FileOutputStream(fileOutPath+i+".png");
                javax.imageio.ImageIO.write(img, "png", out);
            }
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void create2003PPTImage(InputStream in,String fileOutPath){
        try {
            SlideShow slideShow=new SlideShow(in);
            Dimension pgsize = slideShow.getPageSize();
            Slide[] slides=slideShow.getSlides();
            FileOutputStream out = null;
            for(int i = 0;i < slides.length;i++){
                TextRun[] rtruns = slides[i].getTextRuns();
                for(TextRun tr: rtruns){
                    for (RichTextRun index : tr.getRichTextRuns()){
                        index.setFontName("宋体");
                    }
                }
                BufferedImage img=new BufferedImage(pgsize.width,pgsize.height, BufferedImage.TYPE_INT_RGB);
                Graphics2D graphics=img.createGraphics();
                graphics.setPaint(Color.WHITE);
                graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width,pgsize.height));
                slides[i].draw(graphics);
                out = new FileOutputStream(fileOutPath+i+".png");
                javax.imageio.ImageIO.write(img, "png", out);
            }
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void createPPTImage(InputStream in,String fileOutPath){
        try {
            if(!in.markSupported()){
                in=new BufferedInputStream(in);
            }
            if(in.markSupported()){
                in=new PushbackInputStream(in,8);
            }
            File file = new File(fileOutPath);
            if(!file.exists()){
                file.mkdirs();
            }
            if(POIFSFileSystem.hasPOIFSHeader(in)){//2003
                create2003PPTImage(in,fileOutPath);
            }else if(POIXMLDocument.hasOOXMLHeader(in)){//2007
                create2007PPTImage(in,fileOutPath);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

 
生成的图片目录和文件路径在同一位置