第一步 需要下载jar包和jacob-1.14.3-x64.dll
 *   <dependency>
 *      <groupId>net.sf.jacob-project</groupId>
 *      <artifactId>jacob</artifactId>
 *      <version>1.14.3</version>
 *   </dependency>
 *
第二步 把jacob-1.14.3-x64.dll 放到java/bin目录下


电脑环境 win10  office2016
支持文件类型 doc，docx，xls，xlsx,ppt,pptx

下面是源代码
package com.example.demo.xs;

import com.jacob.activeX.ActiveXComponent;
import com.jacob.com.Dispatch;
import com.jacob.com.Variant;

import java.io.File;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * 需要jar包和jacob-1.14.3-x64.dll
 *   <dependency>
 *      <groupId>net.sf.jacob-project</groupId>
 *      <artifactId>jacob</artifactId>
 *      <version>1.14.3</version>
 *   </dependency>
 *
 *  把jacob-1.14.3-x64.dll 放到java/bin目录下
 *
 * 电脑环境 win10  office2016
 * @author 苑庆涛
 * @create 2019-07-22 16:22
 */
public class Test {
    private static Logger logger = Logger.getLogger(WordApp.class.getName());
    public static void main(String[] args) {

    }

    /**
     *  示例 toPdf("d:\\testold\\e3.xls","d:\\testnew\\e3.pdf","xlsx")
     * @param src 文件路径
     * @param tar pdf文件路径
     * @param type 文件类型
     */
    public static void toPdf(String src,String tar,String type){
        if(type.startsWith("doc")){
            wordToPdf(src,tar);
        }else if(type.startsWith("xls")){
            excelToPdf(src,tar);
        }else if(type.startsWith("ppt")){
            pptToPdf(src,tar);
        }
    }
    public static void wordToPdf(String src, String tar) {
        ActiveXComponent app = null;
        Dispatch doc = null;
        try {
            app = new ActiveXComponent("Word.Application");
            app.setProperty("Visible", new Variant(false));
            app.setProperty("AutomationSecurity", new Variant(3));
            Dispatch docs = app.getProperty("Documents").toDispatch();
            doc = Dispatch.call(docs, "Open",
                    src, false, true)
                    .toDispatch();
            File target = new File(tar);
            if (target.exists()) {
                target.delete();
            }
            Dispatch.call(doc, "SaveAs", tar,17);
        } catch (Throwable t) {
            logger.log(Level.SEVERE, t.getMessage(), t);
        } finally {
            if (doc != null) {
                try {
                    Dispatch.call(doc, "Close", false);
                } catch (Throwable t) {
                    logger.log(Level.SEVERE, t.getMessage(), t);
                }
            }
            if (app != null) {
                try {
                    app.invoke("Quit",0);
                    app.safeRelease();
                } catch (Throwable t) {
                    logger.log(Level.SEVERE, t.getMessage(), t);
                }
            }

        }
    }

    public static void excelToPdf(String src, String tar) {
        ActiveXComponent app = null;
        Dispatch doc = null;
        try {
            app = new ActiveXComponent("Excel.Application");
            app.setProperty("Visible", new Variant(false));
            app.setProperty("AutomationSecurity", new Variant(3));
            Dispatch docs = app.getProperty("Workbooks").toDispatch();
            doc = Dispatch.call(docs, "Open", src, false, true)
                    .toDispatch();
            File target = new File(tar);
            if (target.exists()) {
                target.delete();
            }
            Dispatch.call(doc, "ExportAsFixedFormat", 0, tar );
        } finally {
            if (doc != null) {
                try {
                    Dispatch.call(doc, "Close", false);
                } catch (Throwable t) {
                    logger.log(Level.SEVERE, t.getMessage(), t);
                }
            }
            if (app != null) {
                try {
                    app.invoke("Quit");
                    app.safeRelease();
                } catch (Throwable t) {
                    logger.log(Level.SEVERE, t.getMessage(), t);
                }
            }
        }
    }

    public static void pptToPdf(String src, String tar) {
        ActiveXComponent app = null;
        Dispatch doc = null;
        try {
            app = new ActiveXComponent("PowerPoint.Application");
            app.setProperty("AutomationSecurity", new Variant(3));
            Dispatch docs = app.getProperty("Presentations").toDispatch();
            doc = Dispatch.call(
                    docs,
                    "Open", src, true, true,false).toDispatch();
            File target = new File(tar);
            if (target.exists()) {
                target.delete();
            }
            Dispatch.call(doc, "SaveAs",tar,32);
        } finally {
            if (doc != null) {
                try {
                    Dispatch.call(doc, "Close");
                } catch (Throwable t) {
                    logger.log(Level.SEVERE, t.getMessage(), t);
                }
            }
            if (app != null) {
                try {
                    app.invoke("Quit");
                    app.safeRelease();
                } catch (Throwable t) {
                    logger.log(Level.SEVERE, t.getMessage(), t);
                }
            }
        }
    }


}