Upload files... 4

[tarawfp]

I want to creat a web page that allows me to upload file and generate a dynamic link by using the file name...any hints on how to do that

Many Thanks!!

 

[LFI]

JavaScript and HTML.

Using the HTML:

<input type='file' ...>

...will get you the upload-ability. When the user has finished using the 'Browse...' button to find and select a file, the input VALUE attribute will be the path of that file.

You can then use JavaScript to set the destination of a link on the page to that path (if, for example, you want to allow the user to preview the chosen file).

That's not a complete explanation, but does that sound along the lines of what you're asking for?

--Dave

 

[tarawfp]

Thanks Dave, this is what I want to do but can you give me some more code info. about how to do it or direct me to a site that has such information...I need to use both jsp for presentation and servlets for manipulations. and yes I want the user to view the uploaded file. a link leading to the uploaded file should remain on the web page and that file can be viewed by others.

Waiting for your feedback

 

[LFI]

Uploading is a tricky beast (from what I can tell).

You need this in your HTML:

<form name="whatever" method=POST action="yourUpload.jsp" enctype="multipart/form-data">

and an INPUT tag:

<input type='file' name='fileName' size='30' />

Now, what to put in your yourUpload.jsp (the action destination in the FORM tag, above) is dependent upon a lot of things and I'm not sure I can help you there. If I have to do this here, I copy other code we have.

Anyone else?

--Dave

 

[grega]

I'm looking into this at the moment [uploadsing images] and it is indeed a tricky beast - how do you get the binary image from the request object? I've seen comments that you need to write a custom HttpServletRequest, but I'm sure there's some code on the web somewhere to do it. There is some shareware [not for commercial use] that I've seen too.

Greg.

 

[sedj]

As with many things, its not tricky if you know how !
You just need to read the input stream correctly, you don't need any custom objects.

upload prompt html page :

<FORM ACTION="upload.jsp" ENCTYPE="multipart/form-data" METHOD="post" >
	<HR>
	<INPUT TYPE="file" NAME="fileToUpload"> <BR>

	<INPUT TYPE="submit" VALUE="UpLoad">
</FORM>

and the JSP (I would actually put this in a servlet, but as an example) to upload the file and save it on the server :

<!-- upload.jsp -->
<%@ page import="java.io.*" %>

<%
	String contentType = request.getContentType();
	System.out.println("Content type is :: " +contentType);
	if ((contentType != null) && (contentType.indexOf("multipart/form-data") >= 0)) {
		DataInputStream in = new DataInputStream(request.getInputStream());
		int formDataLength = request.getContentLength();

		byte dataBytes[] = new byte[formDataLength];
		int byteRead = 0;
		int totalBytesRead = 0;
		while (totalBytesRead < formDataLength) {
			byteRead = in.read(dataBytes, totalBytesRead, formDataLength);
			totalBytesRead += byteRead;
		}

		String file = new String(dataBytes);
		String saveFile = file.substring(file.indexOf("filename=\"") + 10);
		saveFile = saveFile.substring(0, saveFile.indexOf("\n"));
		saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,saveFile.indexOf("\""));

		int lastIndex = contentType.lastIndexOf("=");
		String boundary = contentType.substring(lastIndex + 1,contentType.length());

		int pos;
		pos = file.indexOf("filename=\"");
		pos = file.indexOf("\n", pos) + 1;
		pos = file.indexOf("\n", pos) + 1;
		pos = file.indexOf("\n", pos) + 1;

		int boundaryLocation = file.indexOf(boundary, pos) - 4;
		int startPos = ((file.substring(0, pos)).getBytes()).length;
		int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;

		FileOutputStream fileOut = new FileOutputStream(saveFile);
		//fileOut.write(dataBytes);
		fileOut.write(dataBytes, startPos, (endPos - startPos));
		fileOut.flush();
		fileOut.close();
		
		out.println("File saved as " +saveFile);
	}
%>

--------------------------------------------------
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http://www.primrose.org.uk

 

[zeero]

sedj, in your code, where is the file being saved at on the server?

 

[LFI]

In sedj's code, creating the FileOutputStream object effectively creates the file on the server. The subsequent writing to the file is writing to the server. No additional saving is required.

--Dave

 

[zeero]

sorry, I meant where it's being created on the server?

 

[tarawfp]

The file is saved in the bin directory of the server. Im still looking into adding a link to the file...any ideas

 

[LFI]

Ah...

In his code, the variable saveFile is not just the file name, but also the path. Control that value and you control where the file goes.

--Dave

 

[zeero]

oh I see, I ran it as an example on windows on tomcat with mysql "as is" and it put it in c:/system32 lol i understand now, Thank You

 

[tarawfp]

Dave,

can you explain more?

 

[LFI]

tarawfp,

start with

http://java.sun.com/j2se/1.4.2/docs/api/java/io/FileOutputStream.html

and see if that explains it for you. I love this particular on-line reference (

http://java.sun.com/j2se/1.4.2/docs/api/index.html)!

--Dave

 

[zeero]

so this code:

saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,saveFile.indexOf("\""));

will put the file you uploaded to C:\WINDOWS\SYSTEM32 for example if you uploaded to a server running windows. however, I'm having syntax problems trying to specify the path I want it saved to. anybody know of an example if i was trying to specify a path on a linux server?

 

[sedj]

The example I originally gave was meant to show you how to upload a file to a server, I was kinda guessing you knew Java ...


This is how you write a file (as the example shows), try to modify the examples to get what you wish for ...

File f = new File("/my/path/to/god/knows/where");
FileOutputStream fos = new FileOutputStream(f);
fos.write("Hello, my name is whatever".getBytes());
fos.flush();
fos.close();

--------------------------------------------------
Free Database Connection Pooling Software

http://www.primrose.org.uk

 

[LFI]

Oops, my bad. I should have noticed the absence of the FILE object. sedj, you did show a STRING object as the parameter in the constructor of the FILEOUTPUTSTREAM in your original code.

Here's some code from a file of mine (it's pretty much the same as sedj's last contribution):

String filePathName = "e:\\iishome\\httpd\\"+fileName;
File myFile = new File(filePathName);

FileWriter newFileWriter = new FileWriter(myFile);
newFileWriter.write(htmlString);
newFileWriter.close();

That was for a FileWriter object. It probably would benefit me to have the .flush() command in there if FileWriter's have one.

'sorry for any confusion.

--Dave

 

[LFI]

I'm stepping back now.

FileOutputStream does have a constructor that takes a STRING argument. Sorry, sedj!

--Dave

 

[zeero]

*bows respectively to sedj*
*bows respectively to Dave*


so the

saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,saveFile.indexOf("\""));

controls where it goes (in that example it's in the bin directory) so for example:

saveFile = saveFile.substring(saveFile.lastIndexOf("\path\to\wherever\") + 1,saveFile.indexOf("\""));

is that all I need to edit to control where the file is going to my server? This is all new to me, sorry for being a noob :/

 

[zeero]

sorry, I worded that last one wrong. What I mean is the lastIndoxOf() method, is that the only part I edit to control the path because it gives me a String -1 error.