CODEWITHSUNDEEP
javafilesimultaneous
Aniket
Aniket

Reputation: 2214

Reading and writing simultaneously java

I am working on java Application where I am dealing with read and write file. But I want to do this process simultaneously. As my file is log file from which I am reading contents by some time interval for this I used java.util.Timer. And during this time interval I am trying to writing some contents in the file, but this is not updating in my log file.

My Timer class is

public class Timer extends java.util.Timer {

 public void startTimer() {
  Timer t = new Timer();
  Task task = new Task();
  t.schedule(task, 0, 10000);
 }
}

My class form which file read write class is called

public class Task extends TimerTask {

 @Override
 public void run() {
  System.out.println("In task ....");
  try {
   SMSQuestions smsQuestions = new SMSQuestions();

   smsQuestions.sendSMSAnswer();
  }
  catch(Exception e)
  {
   e.printStackTrace();
  }
 }
}

My file read write class is

public void sendSMSAnswer()
    {
        long sender;
        String question;

        try {
            BufferedReader br = new BufferedReader(new FileReader("C:/temp/NowSMS/TEST.log"));
            String line = br.readLine();

            while (line != null) {
                sender = 0;
                question = "";
                System.out.println(line);
                line = br.readLine();
            }
            //To delete all contents in file
            BufferedWriter bw = new BufferedWriter(new FileWriter("C:/temp/NowSMS/TEST.log"));
            bw.write("");

            getDetails();

        }catch(Exception exp)
        {
            exp.printStackTrace();
        }
    }

My problem is when i updated my log file by writing new contents it can't be updated so my question is: is it possible in java to simultaneously read write file or not?

Upvotes: 2

Views: 2968

Answers (3)

Ludijor Barros
Ludijor Barros

Reputation: 45

I have two things to say about your code. First: I think that you are missing the finally block where you are supposed to close br and bw. Try: finally {

br.close();
bw.close();

} after the catch block.

Second: It is not a good idea to write content to a file while it is opened. I mean, if you open a file with br maybe it is better to gives another file path to bw

Upvotes: 0

Vegard
Vegard

Reputation: 5082

I would suggest you have a look at random access files (see http://docs.oracle.com/javase/tutorial/essential/io/rafs.html). This API is a little more complicated to work with since you'll be reading bytes, not lines, but it should give you what you need.

If you don't want to deal with NIO you can use http://docs.oracle.com/javase/7/docs/api/java/io/RandomAccessFile.html instead.

Upvotes: 2

Steve Benett
Steve Benett

Reputation: 12943

Try this topic. But the only answer you will get is, its only working with a few OSs.

Upvotes: 0

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