JSP returning XML with one slight flaw....

Question

I have created a web service using JAXB 2.0 which queries a database and returns the queried data as KML (Keyhole Markup Language) for use in Google Earth. The service works great, and is returning the KML just as intended, however, the service is being called by a JSP, which in turn returns the KML by whatever client runs the JSP. I am re-learning JSP after having dabbled in it two years ago, and somewhere along the line the JSP is placing a "\n" (blank line) in the first line, which causes most XML parsers to get very angry at you. The JSP is very simple, and I just dont see where this blank line is coming from:
<%@ page contentType="application/vnd.google-earth.kml+xml; charset=UTF-8" %>
<% try {
com.xxx.kmlpages.KMLWebServiceImplService service = new com.xxx.kmlpages.KMLWebServiceImplService();
com.xxx.kmlpages.KMLWebServiceImpl port = service.getKMLWebServiceImplPort();
java.lang.String result = port.processKML();
out.print(result);
} catch (Exception ex) {
} %>
Normally the xml parser wants to see:
<?xml version="1.0" encoding="UTF-8" ?>
as the first line, but instead the JSP returns that as the second line with a blank line first.
Any idea what in my JSP is causing this blank line?
Message was edited by:
Smiler
I just ran through the debugger, and the "result" which is to be out.print'ed, is exactly as it is supposed to be. There is nothing in the result creating a blank line. So SOMEHOW this very simple JSP is printing a blank line before printing the returned result.

Answer 1

Smiler wrote:
Quite the helpful forum...
After digging around, I came across this webpage:
http://www-128.ibm.com/developerworks/java/library/j-dynxml.html
In it, is described:
"It's important to note that the JSP page compiler will remove only the characters making up the tag and its contents. If you place a JSP tag on a new line, the page compiler will remove everything but the new line (because that is not part of the tag). For example, suppose we add the content type tag to our new JSP page like so:
<%@ page contentType="text/xml;charset=ISO-8859-1" %>
<?xml version="1.0" encoding="ISO-8859-1"?>
<Flights>
<AirCarrier>AA</AirCarrier>
<FlightNumber>700</FlightNumber>
<FlightSegment>
In this case, the page compiler will remove the page directive on the first line, leaving a blank line before the <?xml...?> version tag. In XML documents, the XML version tag must be on the first line, so this example would cause an error in an XML parser."
Well, it seems the simple solution to my problem then is to change my page declarative to:
<%@ page contentType="application/vnd.google-earth.kml+xml" %><%--
--%><% try {
Notice the difference?Hi. I have a similar problem in our program. We are putting the xml in a session and forwarding to jsp where we print it. This is creating a blank first line which causes an error on safari, firefox except ie.
How do you suggest i correct this? Any help /direction in this regard would be appreciated. Thanks!
Rohan