private static final int wdFormatPDF = 17;
 private static final int xlTypePDF = 0;
 private static final int ppSaveAsPDF = 32;
 private static final int msoTrue = -1;
 private static final int msofalse = 0;

jacob 下载地址http://www.oschina.net/code/snippet_128886_43591  使用方法也在

//直接调用这个方法即可
	public boolean convert2PDF(String inputFile, String pdfFile) {
		String suffix =  getFileSufix(inputFile);
		File file = new File(inputFile);
		if(!file.exists()){
			System.out.println("文件不存在！");
			return false;
		}
		if(suffix.equals("pdf")){
			System.out.println("PDF not need to convert!");
			return false;
		}
		if(suffix.equals("doc")||suffix.equals("docx")||suffix.equals("txt")){
			return word2PDF(inputFile,pdfFile);
		}else if(suffix.equals("ppt")||suffix.equals("pptx")){
			return ppt2PDF(inputFile,pdfFile);
		}else if(suffix.equals("xls")||suffix.equals("xlsx")){
			return excel2PDF(inputFile,pdfFile);
		}else{
			System.out.println("文件格式不支持转换!");
			return false;
		}
	}
	public static String getFileSufix(String fileName){
		int splitIndex = fileName.lastIndexOf(".");
        return fileName.substring(splitIndex + 1);
	}
	public boolean word2PDF(String inputFile,String pdfFile){
		try{
		//打开word应用程序
		ActiveXComponent app = new ActiveXComponent("Word.Application");
		//设置word不可见
		app.setProperty("Visible", false);
		//获得word中所有打开的文档,返回Documents对象
		Dispatch docs = app.getProperty("Documents").toDispatch();
		//调用Documents对象中Open方法打开文档，并返回打开的文档对象Document
		Dispatch doc = Dispatch.call(docs,
									"Open",
									inputFile,
									false,
									true
									).toDispatch();
		//调用Document对象的SaveAs方法，将文档保存为pdf格式
		/*
		Dispatch.call(doc,
					"SaveAs",
					pdfFile,
					wdFormatPDF		//word保存为pdf格式宏，值为17
					);
					*/
		Dispatch.call(doc,
				"ExportAsFixedFormat",
				pdfFile,
				wdFormatPDF		//word保存为pdf格式宏，值为17
				);
		//关闭文档
		Dispatch.call(doc, "Close",false);
		//关闭word应用程序
		app.invoke("Quit", 0);
		return true;
	}catch(Exception e){
		return false;
	}
	}
	public boolean excel2PDF(String inputFile,String pdfFile){
		try{
			ActiveXComponent app = new ActiveXComponent("Excel.Application");
		app.setProperty("Visible", false);
		Dispatch excels = app.getProperty("Workbooks").toDispatch();
		Dispatch excel = Dispatch.call(excels,
									"Open",
									inputFile,
									false,
									true
									).toDispatch();
		Dispatch.call(excel,
					"ExportAsFixedFormat",
					xlTypePDF,		
					pdfFile
					);
		Dispatch.call(excel, "Close",false);
		app.invoke("Quit");
		return true;
	}catch(Exception e){
		return false;
	}
		
	}
	public boolean ppt2PDF(String inputFile,String pdfFile){
		try{
		ActiveXComponent app = new ActiveXComponent("PowerPoint.Application");
		//app.setProperty("Visible", msofalse);
		Dispatch ppts = app.getProperty("Presentations").toDispatch();
		
		Dispatch ppt = Dispatch.call(ppts,
									"Open",
									inputFile,
									true,//ReadOnly
									true,//Untitled指定文件是否有标题
									false//WithWindow指定文件是否可见
									).toDispatch();
		
		Dispatch.call(ppt,
					"SaveAs",
					pdfFile,
					ppSaveAsPDF	
					);
				
		Dispatch.call(ppt, "Close");
		
		app.invoke("Quit");
		return true;
		}catch(Exception e){
			return false;
		}
	}

JAVA jacob office转换pdf代码