1、首先将上传的非jpg，pdf格式的文件转成pdf，这个是采用OpenOffice进行转的，具体代码如下：

private void officeToPdf(){

OpenOfficeConnection connection = new SocketOpenOfficeConnection(8100);

try {

connection.connect();

} catch (ConnectException e) {

e.printStackTrace();

}

DocumentConverter converter = new OpenOfficeDocumentConverter(

connection);

converter.convert(officeFile, pdfFile);

// close the connection

connection.disconnect();

}

2、然后将pdf首页转为jpg，具体代码如下：

private  void pdfToJPG(String inputFile) throws IOException { // load a pdf from a byte buffer File file = new File(inputFile); RandomAccessFile raf = new RandomAccessFile(file, "r"); FileChannel channel = raf.getChannel(); ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size()); PDFFile pdffile = new PDFFile(buf); for (int i = 1; i <= pdffile.getNumPages(); i++) { if (i == 1) { // draw the first page to an image // 以图片的形式来描绘首页 PDFPage page = pdffile.getPage(i); // get the width and height for the doc at the default zoom Rectangle rect = new Rectangle(0, 0, (int) page.getBBox() .getWidth(), (int) page.getBBox().getHeight()); // generate the image // 生成图片 Image img = page.getImage(rect.width, rect.height, // width & // height rect, // clip rect null, // null for the ImageObserver true, // fill background with white true // block until drawing is done ); BufferedImage tag = new BufferedImage(rect.width, rect.height, BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(img, 0, 0, rect.width, rect.height, null); FileOutputStream out = new FileOutputStream( imagePath+"\\"+fileName.substring(fileName.lastIndexOf("/")+1) + ".jpg"); // 输出到文件流 JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); encoder.encode(tag); // JPEG编码 // 关闭输出流 out.close(); System.out.println("PDF文件转换JPG文件成功"); } }