show Image from database in jsp

We can provide a servlet as the source of the image. ans in the servlet we need to some little cook. This code may help you in the regards.

/*
* This Method Returns the right MIME type for a particular format
*

* @param String format ex: xml or HTML etc.
* @return String MIMEtype
*/
private String getMimeType(String format)
{
if(format.equalsIgnoreCase("pdf")) //check the out type
return "application/pdf";
else if(format.equalsIgnoreCase("audio_basic"))
return "audio/basic";
else if(format.equalsIgnoreCase("audio_wav"))
return "audio/wav";
else if(format.equalsIgnoreCase("image_gif"))
return "image/gif";
else if(format.equalsIgnoreCase("image_jpeg"))
return "image/jpeg";
else if(format.equalsIgnoreCase("image_bmp"))
return "image/bmp";
else if(format.equalsIgnoreCase("image_x-png"))
return "image/x-png";
else if(format.equalsIgnoreCase("msdownload"))
return "application/x-msdownload";
else if(format.equalsIgnoreCase("video_avi"))
return "video/avi";
else if(format.equalsIgnoreCase("video_mpeg"))
return "video/mpeg";
else if(format.equalsIgnoreCase("html"))
return "text/html";
else if(format.equalsIgnoreCase("xml"))
return "text/xml";
else
return null;
}

Step Two
Get the reference to the right OutPutStream. Use ServletOutPutStream, where as for character data you'd use PrintWriter, the java.io class that prints objects to a text-output stream. This following snippet is for binary data:


ServletOutputStream sOutStream = response.getOutputStream();

Step Three
Create BufferedInputStream from the InputStream:


BufferedInputStream bis = null;
InputStream in = urlc.getInputStream();
bis = new BufferedInputStream(in);




Step Four
Create BufferedOutPutStream with a new ServletOutPutStream to which you can write:


BufferedOutputStream bos = null;
bos = new BufferedOutputStream(sOutStream);

Step Five
Read in to the bytes array from BufferedInputStream:


byte[] buff = new byte[length];
int bytesRead;
// Simple read/write loop.
while(-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
bos.write(buff, 0, bytesRead);
}

Step Six
Write on to BufferedOutPutStream from the bytes array, which in turn streams to the client. Use the streamBinaryData() method for binary data streaming:


/*
* This Method Handles streaming Binary data
*

* @param String urlstr ex: http;//localhost/test.pdf etc.
* @param String format ex: pdf or audio_wav or msdocuments etc.
* @param ServletOutputStream outstr
* @param HttpServletResponse resp
*/
private void streamBinaryData(String urlstr,String format,
ServletOutputStream outstr, HttpServletResponse resp)
{
String ErrorStr = null;
try{
//find the right MIME type and set it as contenttype
resp.setContentType(getMimeType(format));
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try{
URL url = new URL(urlstr);
URLConnection urlc= url.openConnection();
int length = urlc.getContentLength();
resp.setContentLength(length);
// Use Buffered Stream for reading/writing.
InputStream in = urlc.getInputStream();
bis = new BufferedInputStream(in);
bos = new BufferedOutputStream(outstr);
byte[] buff = new byte[length];
int bytesRead;
// Simple read/write loop.
while(-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
bos.write(buff, 0, bytesRead);
}
} catch (Exception e) {
e.printStackTrace();
ErrorStr = "Error Streaming the Data";
outstr.print(ErrorStr);
} finally {
if( bis != null ) {
bis.close();
}
if( bos != null ) {
bos.close();
}
if( outstr != null ) {
outstr.flush();
outstr.close();
}
}
}
catch(Exception e){
e.printStackTrace();
}
}

N.B In the up coming post, i will try to note a complete sequence to show image from database.