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Read and Append data to the File from a Blob URL path before download

This is my first hands on using Java Spring boot in a project, as I have mostly used C# and I have a requirement of reading a file from a blob URL path and appending some string data(like a key) to the same file in the stream before my API downloads the file.
Here are the ways that I have tried to do it:
FileOutputStream/InputStream: This throws a FileNotfoundException as it is not able to resolve the blob path.
URLConnection: This got me somewhere and I was able to download the file successfully but when I tried to write/append some value to the file before I download, I failed.
the code I have been doing.
//EXTERNAL_FILE_PATH is the azure storage path ending with for e.g. *.txt
URL urlPath = new URL(EXTERNAL_FILE_PATH);
URLConnection connection = urlPath.openConnection();
connection.setDoOutput(true); //I am doing this as I need to append some data and the docs mention to set this flag to true.
OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream());
out.write("I have added this");
out.close();
//this is where the issues exists as the error throws saying it cannot read data as the output is set to true and it can only write and no read operation is allowed. So, I get a 405, Method not allowed...
inputStream = connection.getInputStream();
I am not sure if the framework allows me to modify some file in the URL path and read it simultaneously and download the same.
Please help me in understanding if they is a better way possible here.

From logical point of view you are not appending data to the file from URL. You need to create new file, write some data and after that append content from file from URL. Algorithm could look like below:
Create new File on the disk, maybe in TMP folder.
Write some data to the file.
Download file from the URL and append it to file on the disk.
Some good articles from which you can start:
Download a File From an URL in Java
How to download and save a file from Internet using Java?
How to append text to an existing file in Java
How to write data with FileOutputStream without losing old data?

How to download a file from a website?

I was looking for a way to download a file from a website. I've seen this question (How to download and save a file from Internet using Java?) already, but I was wondering if you could clear two things up for me. First, let's say the link to the file is "http://www.mediafire.com/download/fasd13z88k7umvm/SecurityCraft+v1.4pre+for+1.6.4.zip". I would insert the link in the URL constructor:
String url = "http://www.mediafire.com/download/fasd13z88k7umvm/SecurityCraft+v1.4pre+for+1.6.4.zip";
URL website = new URL(url);
ReadableByteChannel rbc = Channels.newChannel(website.openStream());
FileOutputStream fos = new FileOutputStream("information.html");
fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
but what needs to be inserted in the FileOutputStream constructor? And the second thing is, where would fos.getChannel().transferFrom() save the file to? Or do I need to do another step to save the file to my hard drive?
Anyway, thanks for reading.

In answer to your first question, you put the filename of where you want to save the file. See the docs here.. And I think that answers your second question, since the string is where you want to save the file.
Just remember if you use a relative path, the file will save where the application is executed, and you also need to make sure you have write access to that directory.

How can I return the file path using the JNLP file chooser

Hi I am trying to get the returned file path by my JNLP file chooser. Here's my code.
I don't know how and where to get the file path. is it from fileContents? fileConents.getfilepath something like that?
try {
if (fileOpenService==null) {
fileOpenService = (FileOpenService)ServiceManager.
lookup("javax.jnlp.FileOpenService");
}
fileContents = fileOpenService.openFileDialog(path, xtns);
} catch(UnavailableServiceException use) {
use.printStackTrace();
} catch(IOException ioe) {
ioe.printStackTrace();
}
Thanks in advance!

According to http://docs.oracle.com/javase/tutorial/uiswing/components/filechooser.html
You can call other methods on the File object, such as
getPath, isDirectory, or exists to obtain information about the file.
You can also call other methods such as delete and rename to change
the file in some way. Of course, you might also want to open or save
the file by using one of the reader or writer classes provided by the
Java platform. See Basic I/O for information about using readers and
writers to read and write data to the file system.

It is for security reasons that a FileContents will not return a path. The JRE asked the user if our app. could access the content of that file, not it's path.
It is a bit like the brower/HTML based file upload field. Some browsers provide the entire path, while more typically it is just the content/name.

Java URL problem

A webpage contains a link to an executable (i.e. If we click on the link, the browser will download the file on your local machine).
Is there any way to achieve the same functionality with Java?
Thank you

Yes there is.
Here a simple example:
You can have a JSF(Java Server Faces) page, with a supporting backing bean that contains a method annotated with #PostConstruct This means that any action(for example downloading), will occur when the page is created.
There is already a question very similar already, have a look at: Invoke JSF managed bean action on page load

You can use Java's, URL class to download a file, but it requires a little work. You will need to do the following:
Create the URL object point at the file
Call openStream() to get an InputStream
Open the file you want to write to (a FileOutputStream)
Read from the InputStream and write to the file, until there is no more data left to read
Close the input and output streams
It doesn't really matter what type of file you are downloading (the fact that it's an executable file is irrelevant) since the process is the same for any type of file.
Update: It sounds like what you actually want is to plug the URL of a webpage into the Java app, and have the Java app find the link in the page and then download that link. If that is the case, the wording of your question is very unclear, but here are the basic steps I would use:
First, use steps 1 and 2 above to get an InputStream for the page
Use something like TagSoup or jsoup to parse the HTML
Find the <a> element that you want and extract its href attribute to get the URL of the file you need to download (if it's a relative URL instead of absolute, you will need to resolve that URL against the URL of the original page)
Use the steps above to download that URL
Here's a slight shortcut, based on jsoup (which I've never used before, I'm just writing this from snippets stolen from their webpage). I've left out a lot of error checking, but hey, I usually charge for this:
Document doc = Jsoup.connect(pageUrl).get();
Element aElement = doc.getElementsByTag("a").first() // Obviously you may need to refine this
String newUrl = aElement.attr("abs:href"); // This is a piece of jsoup magic that ensures that the destination URL is absolute
// assert newUrl != null
URL fileUrl = new URL(newUrl);
String destPath = fileUrl.getPath();
int lastSlash = destPath.lastIndexOf('/');
if (lastSlash != -1) {
destPath = destPath.substring(lastSlash);
}
// Assert that this is really a valid filename
// Now just download fileUrl and save it to destPath
The proper way to determine what the destination filename should be (unless you hardcode it) is actually to look for the Content-Disposition header, and look for the bit after filename=. In that case, you can't use openStream() on the URL, you will need to use openConnection() instead, to get a URLConnection. Then you can use getInputStream() to get your InputStream and getRequestProperty("Content-Disposition") to get the header to figure out your filename. In case that header is missing or malformed, you should then fall-back to using the method above to determine the destination filename.

You can do this using apache commons IO FileUtils
http://commons.apache.org/io/apidocs/org/apache/commons/io/FileUtils.html#copyURLToFile(java.net.URL, java.io.File)
Edit:
I was able to successfully download a zip file from source forge site (it is not empty), It did some thing like this
import java.io.File;
import java.net.URL;
import org.apache.commons.io.FileUtils;
public class Test
{
public static void main(String args[])
{
try {
URL url = new URL("http://sourceforge.net/projects/gallery/files/gallery3/3.0.2/gallery-3.0.2.zip/download");
FileUtils.copyURLToFile(url, new File("test.zip"));
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
I was able successfully download tomcat.exe too
URL url = new URL("http://archive.apache.org/dist/tomcat/tomcat-6/v6.0.16/bin/apache-tomcat-6.0.16.exe");

Using a button to export sqlite db to an excel-readable file (perhaps csv)?

I adapted this tutorial (http://www.screaming-penguin.com/node/7749) to an Android app I've built to allow for a button press to export the current database to the user's sdcard. It works flawlessly.
But I'm afraid that users of my app would be unfamiliar with the db file, and I'm looking for a way to convert that to a more user-friendly format. I came across this thread (http://groups.google.com/group/android-beginners/browse_thread/thread/4e53ebca14daecfc), which recommends "querying data from the database and writing the data into a csv file."
I was hoping someone could point me in the right direction to begin figuring out how to do this. I'm finding it hard to track down more information about the specific method.
Or does it make more sense to just explain in a short "about" how to read and access .db files?
Thanks
EDIT: I also have a question about the sqlite export process, which I think I'll just ask here rather than create a new question. Is there a way to modify the code below so that each export would receive either a string representation of the date or just a single numeral appended to it? Right now if you export a second time, it automatically overwrites the old file. Thanks.
protected Boolean doInBackground(final String... args) {
File dbFile = new File(Environment.getDataDirectory() +
"/data/com.example.example/databases/data");
File exportDir = new File(Environment.getExternalStorageDirectory(), "exampledata");
if (exportDir.exists()) {
exportDir.mkdirs();
}
File file = new File(exportDir, dbFile.getName());
try {
file.createNewFile();
this.copyFile(dbFile, file);
return true;
} catch(IOException e) {
Log.e(MyApplication.APP_NAME, e.getMessage(), e);
return false;
}
}

I was hoping someone could point me in the right direction to begin figuring out how to do this.
To read in the data, use rawQuery().
To write the data, use Java I/O. There are also open source CSV libraries for Java that may work on Android.
Is there a way to modify the code below so that each export would receive either a string representation of the date or just a single numeral appended to it?
Use string concatenation to add whatever you want to the filename.
Also, please get rid of:
File dbFile = new File(Environment.getDataDirectory() +
"/data/com.example.example/databases/data");
and replace it with:
File dbFile=getDatabasePath("data");