JSP/Servlet : How to Read an image via URL and render it on a JSP page (image URL is not public)
what's the best approach to read an image via URL and render it on a JSP page?
so far, I've coded two JSP pages.
EDIT START:
*Experimental: Obviously the ImageServ will be a servlet, not a jsp.
EDIT END:
index.jsp
<%page ....
<html>
......
<img src="ImageServ.jsp?url=http://serveripaddress/folder/image.jpg" />
.....
ImageServ.jsp
<%@page import="javax.imageio.ImageIO"%>
<%@page import="java.net.URL"%>
<%@page import="java.io.*, java.awt.*, java.awt.image.*,com.sun.image.codec.jpeg.*" %>
<%
try {
String urlStr = "";
if(request.getParameter("url") != null)
{
urlStr = request.getParameter("url");
URL url = new URL(urlStr);
BufferedImage img = null;
try{
img = ImageIO.read(url);
out.println(" READ SUCCESS" + "<br>");
}catch(Exception e) {
out.println("READ ERROR " + "<br>");
e.printStackTrace(new PrintWriter(out));
}
try {
response.setContentType("image/jpeg");
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(response.getOutputStream());
开发者_运维技巧 encoder.encode(img);
}catch(Exception ee) {
response.setContentType("text/html");
out.println("ENCODING ERROR " + "<br>");
ee.printStackTrace(new PrintWriter(out));
}
}
} catch (Exception e) {
e.printStackTrace(new PrintWriter(out));
}
%>
But this doesn't seem to be working: all the time i see this error:
READ SUCCESS
ENCODING ERROR
java.io.IOException: reading encoded JPEG Stream
at sun.awt.image.codec.JPEGImageEncoderImpl.writeJPEGStream(Native Method)
at sun.awt.image.codec.JPEGImageEncoderImpl.encode(JPEGImageEncoderImpl.java:476)
at sun.awt.image.codec.JPEGImageEncoderImpl.encode(JPEGImageEncoderImpl.java:228)
Any ideas on how to get this working???
Your image data is already encoded so you can simply write it: ImageIO.write(img, "jpeg", response.getOutputStream());. You don't need to (and can't) use JPEGImageEncoder.
Classic question. Here's an example: http://www.exampledepot.com/egs/javax.servlet/GetImage.html
Also, don't do all that coding in a JSP - keep that for front-end rendering coding only; do the Java coding in a backend class.
Terrible and awful code. NEVER EVER write controller logic in a JSP that's why I have JSP to the guts. You cannot write binary data to a JSP output stream. The stream has already been initialized for text output. Put your logic in a servlet and pipe the input stream to the response output stream with Commons IO. This will work. If you still insist on that crappy solution, you will need to write a filter which completely wraps the response and serves binary data instead. See this for reference and examine its code. Good luck.
Edit:
doGet(...) {
response.setContentType("image/jpeg");
String url = request.getParameter("url");
...
InputStream is = ....getInputStream();
IOUtils.copy(is, response.getOutputStream());
// cleanup
} // done
This is how I pipe PDF from local disk but there is no difference to serving from a URL.
加载中,请稍侯......
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