Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

FileOutputStream can't create file

Posted on 2011-02-27
10
781 Views
Last Modified: 2012-05-11
Hi,

I am using the attached code to create a file, but exception was thrown out:

"The system cannot find the path specified"

This is the file I wanted to create:

c:/crawl_data/2011-02-27/guansheng/1233445dfaf+guansheng+T¿+2011-02-27_10-42-05+1.html

I also try to create the directory "c:/crawl_data/2011-02-27/guansheng/" first, but I can't create the directory with the second code piece.

I also did some research that I need to create the file before I use FileOutputStream to write to it. Is it true? How can I create and write to a file on the fly?

Thanks



String base_dir="c:/crawl_data/";
		String dir=ts.substring(0, 10)+"/"+domain+"/";
		String filename=code+"+"+domain+"+"+prod+"+"+ts+"+"+order+".html";
		try {
			byte[] utf8 = content.getBytes("UTF-8");
			File afile = new File(base_dir+dir+filename);
			System.out.println(base_dir+dir+filename);
			if(!afile.exists()){
				if(afile.createNewFile()){
					FileOutputStream out = new FileOutputStream(afile);
					out.write(utf8);
					out.close();
				}
			}
			
		} catch (UnsupportedEncodingException e) {
			System.out.println("UTF-8¿¿¿¿:code="+code+ "\n"+e.getMessage());
			return false;
		} catch (FileNotFoundException e) {
			System.out.println("¿¿¿¿¿:code="+code+ "\n"+e.getMessage());
			return false;
		} catch (IOException e) {
			System.out.println("IO¿¿:code="+code + "\n"+e.getMessage());
			return false;
		}

Open in new window

String dir = "c:/crawl_data/2011-02-27/guansheng/";
if((new File(dir)).mkdir()){
   System.out.println("done");
}

Open in new window

0
Comment
Question by:wsyy
  • 6
  • 4
10 Comments
 
LVL 47

Expert Comment

by:for_yan
ID: 34994240
I guess, that means that you don't have upper folders in existyence.
If you use mkdirs() instead of mkdir() it will create all upper folders which are ecessary simpulatenoisly
0
 
LVL 47

Expert Comment

by:for_yan
ID: 34994245
However if you believe that upper path, say c:/crawl_data/2011-02-27/ should already be in existence, then
it is worth investigating more why such error appears before you use mkdirs() instead of mkdir()
0
 
LVL 47

Expert Comment

by:for_yan
ID: 34994252
If your path to the folder where you want to place your output file exists, then you don't need to create file in a special operator- just
writing through FileoutputStream should be enough. If the folder itself does not exist - it will thow an exception, but if the folder exists - file
willbe created on the fly
0
Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 

Author Comment

by:wsyy
ID: 34994284
for_yan, the directories are not in existent beforehand.

I change my code as below:

if(!afile.exists()){
                        if(afile.mkdirs()){
                              FileOutputStream out = new FileOutputStream(afile);
                              out.write(utf8);
                              out.close();
                        }
                  }

Note please that I now use mkdirs(). This time an FileNotFoundException exception was thrown out, together with "Access denied" info.

Why these two can be thrown out together? which is the main reason?
0
 
LVL 47

Accepted Solution

by:
for_yan earned 125 total points
ID: 34994308
I'm not sure you can have the afile.mkdirs() and point output stream to FileOutputStream(afile)

afile.mksdirs() - here afile should be directory

output stream should be directed to the file so you need to create file form the directory string + filename

so if  String f is the name of the fiolder, then f.mkdirs() will create the folder.
but File f1 shoulde be f1 = new File(f + Systsem.getProperty("file.separator') + n); where n - is the name of the actual file.

There may be also other reasons, but this is waht comes immediately when I looked at your code
 


0
 

Author Comment

by:wsyy
ID: 34994358
for_yan, you are right. I need to separate the directory from the file.

one last question: how can I specify the read-only permission to the newly created file? Is it something that can be done by Java?
0
 
LVL 47

Expert Comment

by:for_yan
ID: 34994362
0
 

Author Comment

by:wsyy
ID: 34994455
the example shows how to set permission to a folder, right? how can i set it on file level?
0
 

Author Comment

by:wsyy
ID: 34994463
in addition, when i changed my code as follow:

File afile = new File(dir);
                  if(!afile.exists()){
                        if(afile.mkdirs()){
                              File f = new File(dir+filename);
                              f.setReadOnly();
                              FileOutputStream out = new FileOutputStream(f);
                              out.write(utf8);
                              out.close();
                        }
                  }

I can still modify and save the file which is supposed to be read-only.
0
 
LVL 47

Expert Comment

by:for_yan
ID: 34994473

No, the API implies that in this case it should work in the same format for both File and Directory
http://download.oracle.com/javase/1.5.0/docs/api/java/io/File.html#setReadOnly%28%29

Still I guess how well it works  very much depends on the underlying OS.
Check, in you case and if it does not work, then on Unix system
you can use the system command chmod, through the call like Runtime.getRuntime().exec("chmod...") from your java code
Perhaps there is something similar on Windows also
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Should localization be done inside spring controller 5 32
java stored proc example 9 45
Running JavaFX on JDeveloper 12C 1 55
java mysql insert application 14 29
INTRODUCTION Working with files is a moderately common task in Java.  For most projects hard coding the file names, using parameters in configuration files, or using command-line arguments is sufficient.   However, when your application has vi…
By the end of 1980s, object oriented programming using languages like C++, Simula69 and ObjectPascal gained momentum. It looked like programmers finally found the perfect language. C++ successfully combined the object oriented principles of Simula w…
This video teaches viewers about errors in exception handling.
This tutorial explains how to use the VisualVM tool for the Java platform application. This video goes into detail on the Threads, Sampler, and Profiler tabs.

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question