我有ShowPresentation.jsp从计算机上传 PPT 文件并通过 java servlet 将每张幻灯片转换为图像的方法。
那我需要NodeJS实时分享，怎么做？这是ShowPresentation.jsp内容。
<!DOCTYPE >
<html>
<head>
<script type="text/javascript">
var current_slide_number = 1;
function button(slideNumber){
current_slide_number = current_slide_number + slideNumber;
var image = document.getElementById('imageslide');
var fileName = document.getElementById('hidFileName');
image.src = 'Viewer?slideNumber='+current_slide_number+'&hidFileName='+fileName.value;
}
</script>
<title>PowerPoint to JPEG</title>
</head>
<body>
<div>
<form method="post" action="Viewer" enctype="multipart/form-data" >
<p >
Upload a file:</p>
<input type="file" name="datafile" size="40"> <input type="submit" value="Upload">
</form>
</div>
<% if (request.getAttribute("fileName") != null) {
%>
<div id="slide-controls">
<b>Please navigate through the slides</b>
</div>
<div id="slide"><p align="center">
<img id="imageslide" src="Viewer?hidFileName=<%=request.getAttribute("fileName")%>"></img>
</p>
</div>
<% }%>
<input id="hidFileName" type="hidden" value="<%=request.getAttribute("fileName")%>"></input>
和这个 servlet 内容 Viewer.java
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.poi.hslf.model.Slide;
import org.apache.poi.hslf.usermodel.SlideShow;
public class Viewer extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int slideNumber = 1;
BufferedImage image = null;
ServletOutputStream os = null;
try{
if (request.getParameter("hidFileName") != null){
String fileName = request.getParameter("hidFileName");
if(request.getParameter("slideNumber") != null)
slideNumber = Integer.parseInt(request.getParameter("slideNumber"));
image = getSlideAsImage(fileName, slideNumber);
os = response.getOutputStream();
ImageIO.write(image, "jpeg", os );
}
else {
response.sendRedirect("StartPresentation.jsp");
}
}
catch (Exception e){
if (os != null)
os.close();
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String contentType = request.getContentType();
String realPath = getServletContext().getRealPath("/");
if ((contentType != null) && (contentType.indexOf("multipart/form-data") >= 0))
{
DataInputStream in = new DataInputStream(request.getInputStream());
int formDataLength = request.getContentLength();
byte dataBytes[] = new byte[formDataLength];
int byteRead = 0;
int totalBytesRead = 0;
while (totalBytesRead < formDataLength) {
byteRead = in.read(dataBytes, totalBytesRead, formDataLength);
totalBytesRead += byteRead;
}
String file = new String(dataBytes);
String saveFile = file.substring(file.indexOf("filename=\"") + 10);
saveFile = saveFile.substring(0, saveFile.indexOf("\n"));
saveFile = saveFile.substring(saveFile.lastIndexOf("\\")+ 1, saveFile.indexOf("\""));
int lastIndex = contentType.lastIndexOf("=");
String boundary = contentType.substring(lastIndex + 1, contentType.length());
int pos;
pos = file.indexOf("filename=\"");
pos = file.indexOf("\n", pos) + 1;
pos = file.indexOf("\n", pos) + 1;
pos = file.indexOf("\n", pos) + 1;
int boundaryLocation = file.indexOf(boundary, pos) - 4;
int startPos = ((file.substring(0, pos)).getBytes()).length;
int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;
System.out.println("After File Name: "+ saveFile);
String filePath = realPath + "/" + saveFile;
FileOutputStream fileOut = new FileOutputStream(filePath);
fileOut.write(dataBytes, startPos, (endPos - startPos));
fileOut.close();
request.setAttribute("fileName", saveFile);
getServletContext().getRequestDispatcher("/StartPresentation.jsp").forward(request, response);
}
}
private BufferedImage getSlideAsImage(String fileName, int slideNumber) throws Exception
{
BufferedImage image = null;
String realPath = getServletContext().getRealPath("/");
String filePath = realPath + "/" + fileName;
FileInputStream in = new FileInputStream(filePath);
SlideShow ppt = new SlideShow(in);
Slide[] slides = ppt.getSlides();
Dimension pgsize = ppt.getPageSize();
image = new BufferedImage(pgsize.width, pgsize.height,BufferedImage.TYPE_INT_RGB);
Graphics2D graphics = image.createGraphics();
graphics.setPaint(Color.white);
graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width, pgsize.height));
if (slideNumber < 1)
slideNumber = 1;
else if (slideNumber > slides.length)
slideNumber = slides.length;
slides[slideNumber - 1].draw(graphics);
return image;
}
}