Develop Reference

FileNotFound while File is there

I am using getClassLoader().getResources to find the path for Jsoup to parse.
String path = JsoupDemo1.class.getClassLoader().getResource("student.xml").getPath();
Document document = Jsoup.parse(new File(path), "utf-8");
Elements names = document.getElementsByTag("name");
System.out.println(names.size());
My student.xml has been placed under the src folder in my module "day11_xml" and this code snippet comes from the class JsoupDemo1 in the package cn.itcast.xml.jsoup under the same module of "day11_xml". The error messages reads as follows:
java.io.FileNotFoundException:/Users/dingshun/Downloads/New%20Java%20Projects/demo/out/production/day11_xml/student.xml (No such file or directory)
I don't get it, as I can find the exact file in the given path. I'm confused, but could you guys help me out? Also, I'm new to both Java programming and this forum and if this question sounds silly or my question format is not right, please let me know.

What you're doing looks good. Maybe use the stream version JSoup.parse.
URL url = JsoupDemo1.class.getClassLoader().getResource("student.xml");
InputStream stream = JsoupDemo1.class.getClassLoader().getResourceAsStream("student.xml");
document = Jsoup.parse(stream, "utf-8", url.toURI()toString());
The documentation linked seems to imply it will work with html not xml, so maybe you need to use the other argument which provides a parser?

Actually, it turned out that Jsoup could not find my file because the path name "New%20Java%20Projects" has spaces between them. When I reload the file in a folder which has no spaces in its name, it works out just fine. So it can parse xml using parse​(File in, String charsetName) method. It seems it cannot parse path name which has spaces in it.

Blank PDF while downloading

I am facing a very strange issue, I am trying to send the PDF file as attachment from my struts application using below code,
JasperReport jrReport = (JasperReport) JRLoader.loadObject(jasperReport);
JasperPrint jasperPrint = JasperFillManager.fillReport(jrReport, parameters, dataSource);
jasperPrint.setName(fileNameTobeGivenToExportedReport);
response.reset();
response.setContentType("application/pdf");
response.setHeader("Content-Disposition", "attachment; filename=\"" + fileNameTobeGivenToExportedReport + ".pdf" + "\"");
response.setHeader("Cache-Control", "private");
JasperExportManager.exportReportToPdfStream(jasperPrint, response.getOutputStream());
but the PDF that is being downloaded is coming with no data, means it is showing the blank page.
When in the above code I added the below line to save the PDF file in my D: directory
File pdf = new File("D:\\sample22.pdf");
JasperExportManager.exportReportToPdfStream(jasperPrint, new FileOutputStream(pdf));
The file that is getting generated is proper, mean with all the data. One thing that I noticed that the file that is downloading from browser and "sample22.pdf" have same size.
I read an article that says that it might be an issue with server configuration as our server might be corrupting the output stream. This is the article that I read Creating PDF from Servlet.
This article says
This can happen when your server flattens all bytes with a value higher than 127. Consult your web (or application) server manual to find out how to make sure binary data is sent correctly to the browser.
I am using struts 1.x, jBoss6, iReport 1.2

Suppose that you have a simple "Hello World" PDF document:
When you open this document, you see that the file structure uses ASCII characters, but that the actual content of the page is compressed to a binary stream:
You don't see the words "Hello World" anywhere, they are compressed along with the PDF syntax that contains info needed to draw these words on the page into this stream:
xœ+är
á26S°00SIá2PÐ5´ 1ôÝBÒ¸4<RsròÂó‹rR5C²€j#*\C¸¹ Çq°
Now suppose that a process shave all the non-ASCII characters into ASCII. I've done this manually as you can see in the next screen shot:
I can still open the document, because I didn't change anything to the file structure: there is still a /Pages three with a single /Page dictionary. From the syntactical point of view, the file looks OK, so I can open it in Adobe Reader:
As you can see, the words "Hello World" are gone. The stream containing the syntax to render these words were corrupted (in my case manually, in your case by the server, or by Struts, or by whatever process you are using that thinks you are creating plain text instead of a binary file).
What you need to do, is to find the place where this happens. Maybe Struts is the culprit. Maybe you are (unintentionally) using Struts as if you were creating a plain text file. It is hard to tell remotely. This is a typical problem caused by a configuration issue. Only somebody with access to your configuration can solve this.

Java Servlet: how to escape the pound character when setting response header?

My Java servlet includes the following line:
response.addHeader("Content-Disposition", "filename=myFile.pdf");
I need to include a named destination defined in the PDF file as part of the file name. Ideally, I could use the following:
response.addHeader("Content-Disposition", "filename=myFile.pdf#Chapter3");
but when I run it, the url in the browser shows /path/to/myFile.pdf%23Chapter3 instead of the desired /path/to/myFile.pdf#Chapter3.
How to escape the # in "filename=myFile#Chapter3"? Escaping with \ gives a compile-time error. Escaping with &035; doesn't work either.

RFC 2616 defines that "the Content-Disposition response-header field has been proposed as a means for the origin server to suggest a default filename if the user requests that the content is saved to a file" so I don't think you can do what you intend to through your servlet. Maybe you will have better luck with some script in the pdf : you could imagine parsing its own name to dynamically set it at the right anchor at opening.

reading an html with matlab

I would like to read some html using matlab.
I've already tried urlread but got the url read error
Getting data into MATLAB from HTTPS:
so i tried using java with this:
Handling an invalid security certificate using MATLAB's urlread command.
unfortunately i don't know how to use java with matlab.
so i tried this code and it seems to work
url = 'https://stackoverflow.com/questions/11053664/use-java-in-matlab';
is = java.net.URL([], url ).openConnection().getInputStream();
br = java.io.BufferedReader(java.io.InputStreamReader(is));
str = char(br.readLine());
however i would like to get the whole html page. so i can use regexp.
My kingdom for some help

There is a function in matlab that does that... The name is urlread!
See http://www.mathworks.com/matlabcentral/answers/973

How to parse an XML file containing BOM?

I want to parse an XML file from URL using JDOM. But when trying this:
SAXBuilder builder = new SAXBuilder();
builder.build(aUrl);
I get this exception:
Invalid byte 1 of 1-byte UTF-8 sequence.
I thought this might be the BOM issue. So I checked the source and saw the BOM in the beginning of the file. I tried reading from URL using aUrl.openStream() and removing the BOM with Commons IO BOMInputStream. But to my surprise it didn't detect any BOM.
I tried reading from the stream and writing to a local file and parse the local file. I set all the encodings for InputStreamReader and OutputStreamWriter to UTF8 but when I opened the file it had crazy characters.
I thought the problem is with the source URL encoding. But when I open the URL in browser and save the XML in a file and read that file through the process I described above, everything works fine.
I appreciate any help on the possible cause of this issue.

That HTTP server is sending the content in GZIPped form (Content-Encoding: gzip; see http://en.wikipedia.org/wiki/HTTP_compression if you don't know what that means), so you need to wrap aUrl.openStream() in a GZIPInputStream that will decompress it for you. For example:
builder.build(new GZIPInputStream(aUrl.openStream()));
Edited to add, based on the follow-up comment: If you don't know in advance whether the URL will be GZIPped, you can write something like this:
private InputStream openStream(final URL url) throws IOException
{
final URLConnection cxn = url.openConnection();
final String contentEncoding = cxn.getContentEncoding();
if(contentEncoding == null)
return cxn.getInputStream();
else if(contentEncoding.equalsIgnoreCase("gzip")
|| contentEncoding.equalsIgnoreCase("x-gzip"))
return new GZIPInputStream(cxn.getInputStream());
else
throw new IOException("Unexpected content-encoding: " + contentEncoding);
}
(warning: not tested) and then use:
builder.build(openStream(aUrl.openStream()));
. This is basically equivalent to the above — aUrl.openStream() is explicitly documented to be a shorthand for aUrl.openConnection().getInputStream() — except that it examines the Content-Encoding header before deciding whether to wrap the stream in a GZIPInputStream.
See the documentation for java.net.URLConnection.

You might find you can avoid handling encoded responses by sending a blank Accept-Encoding header. See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html: "If no Accept-Encoding field is present in a request, the server MAY assume that the client will accept any content coding.". That seems to be occurring here.