Java, what to use instead of PrintStream to get exceptions?

Question

I am creating a file on a network drive and then adding data to it. Time to time writing to that file fails. Is there a good way of checking if the file is accessible before every time i save data to it or maybe is tehre a way checking afther to see if the data was saved?

EDIT: Right now i am using try-catch block with PrintStream in my code:

        try
        {
            logfile = new File(new File(isic_log), "log_" + production);
            //nasty workaround - we'll have a file the moment we assign an output stream to it
            if (!logfile.exists())
            {
                    prodrow = production;
            }

            out = new FileOutputStream(logfile.getPath(), logfile.exists());
            p = new PrintStream(out);
            if (prodrow != "")
            {
                p.println (prodrow);
            }
            p.println (chip_code + ":" + isic_number);
            p.close();
        }
        catch (Exception e)
        {
                logger.info("Got exception while writing to isic production log: " + e.getMessage());
        }

So might be the PrintStream the problem? (PrintWriter and PrintStream never throw IOExceptions)

doesn't it throw an exception when it fails? checking first wouldn't help all that much because it could become unavailable at any point during the write. — jcomeau_ictx, May 04 '11 at 08:47
Checking whether a file is accessible before opening it leads to race conditions, esp. in the case of a networked filesystem. — Fred Foo, May 04 '11 at 08:48

Peter Lawrey · Accepted Answer · 2011-05-04T09:20:44.117

2

I would use plain BufferedWriter and add the newlines myself as required.

Normal FileOutputStream operations should throw an IOException if there is an error.

AFAIK, The only exception is PrintWriter which does not throw an exception. Instead you need to call checkError() but it gives you no indication of what the error was or when it occurred.

I suggest you not use PrintWriter in this situation.

edited May 04 '11 at 09:20

answered May 04 '11 at 08:50

Peter Lawrey

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FYI: Im using PrintStream in there right now. Found this thread: http://stackoverflow.com/questions/297303/printwriter-and-printstream-never-throw-ioexceptions – hs2d May 04 '11 at 08:59

score 1 · Answer 2 · answered May 04 '11 at 08:49

The only reasonable way to address this is to try to write to the file, and handle any resulting exception in an appropriate manner. It's pretty much impossible to know beforehand whether an I/O operation is going to succeed, due to the unreliable nature of networks.

Java, what to use instead of PrintStream to get exceptions?

2 Answers2