Slow file access

Question

I have a class that just does some trace logging and it is extremely slow
          when used with a servlet, but is very fast when used otherwise. The class
          is basically just the following:
          Date date = new Date();
          SimpleDateFormat formatter = new SimpleDateFormat ("MM/dd/yyyy HH:mm:ss");
          DataOutputStream dos = new DataOutputStream( new
          ileOutputStream( logFileName, true ) );
          dos.writeBytes( formatter.format(date)+" "+logIdStr+" "+msg+"\r\n" );
          dos.close();
          I added a flag that would skip around all the logic in the write method of
          this class so I could time the servlet without it and found it takes 10
          seconds longer to run the servlet with this logic being run to create a
          couple thousand traces. Any idea why it would be so slow?
          

Answer 1

May be this is because the DataOutputStream class is intended to write
          java primitive types in a binary portable format, so it could make CPU
          intensive checking and conversion ?
          For textual output, it should be better to use PrintWriter.
          Can you check CPU usage ? You can download OptimizeIt! and profile your
          code.
          Note also you open and close a file. How is your disk's fragmentation ?
          Finally it is more efficient to use a StringBuffer to produce the output
          string before passing to a method.
          David Thompson wrote:
          >
          > I have a class that just does some trace logging and it is extremely slow
          > when used with a servlet, but is very fast when used otherwise. The class
          > is basically just the following:
          > Date date = new Date();
          > SimpleDateFormat formatter = new SimpleDateFormat ("MM/dd/yyyy HH:mm:ss");
          > DataOutputStream dos = new DataOutputStream( new
          > ileOutputStream( logFileName, true ) );
          > dos.writeBytes( formatter.format(date)+" "+logIdStr+" "+msg+"\r\n" );
          > dos.close();
          > I added a flag that would skip around all the logic in the write method of
          > this class so I could time the servlet without it and found it takes 10
          > seconds longer to run the servlet with this logic being run to create a
          > couple thousand traces. Any idea why it would be so slow?