Solved

redirecting throwable.printStackTrace

Posted on 1998-03-12
7
217 Views
Last Modified: 2011-09-20
I would like to re-direct the stack trace of an exception to a String (so that I can write it to a log file).
Ideally, I would like a PrintStream class that writes to a String buffer.
0
Comment
Question by:sprinkmeier
  • 4
  • 3
7 Comments
 
LVL 6

Accepted Solution

by:
jpk041897 earned 100 total points
ID: 1233524
If you look at  java.lang.trowable.printStackTrace docs, you will find an impementation for:

public void printStackTrace(PrintStream s)
 
Prints this Throwable and its backtrace to the  specified print stream.  

By using this method, you can create a PrintStream derived class that writes to any place you want (disk, printer, stdout, etc) and solve your problem. The trick is to use the throwable implementation.
0
 
LVL 2

Author Comment

by:sprinkmeier
ID: 1233525
OK, I know hot to print the stack trace to a PrintStream, but how do I create a Printstream that outputs to a String buffer?

I know it's in the DOC's somewhere, and if I had them, I would not be asking this question.
0
 
LVL 6

Expert Comment

by:jpk041897
ID: 1233526
OK,

ByteArrayOutputStream out = new ByteArrayOutputStream();

PrintStream ps = new PrintStream(out);

// You now have a Print Stream that writes to a buffer array.

...

// Inside an exception handler you could now use:

printStackTrace(ps);

String Buffer = ps.toString();

// Now you can use Buffer in whatever way you require.
0
Efficient way to get backups off site to Azure

This user guide provides instructions on how to deploy and configure both a StoneFly Scale Out NAS Enterprise Cloud Drive virtual machine and Veeam Cloud Connect in the Microsoft Azure Cloud.

 
LVL 2

Author Comment

by:sprinkmeier
ID: 1233527
/*

To Compile:
  javac exc_2_string.java
 
To Run:
  java  exc_2_string

*/
class exc_2_string
{

  public static void main(String args[])
  {
    try{
      System.out.println("Throwing a wobbly");
      // create and throw an exception
      Exception x = new Exception("ASDF");
      throw(x);
    } catch (Exception x) {
      System.out.println("Exception caught");
      // Create a place to stick the data
      java.io.ByteArrayOutputStream out = new java.io.ByteArrayOutputStream();
/*            
      java.io.PrintStream ps = new java.io.PrintStream(out);

  PrintStream is replaced, use PrintWriter instead. Only differance
  seems to be that the PrintWriter must be flush()-ed before you
  examine the ByteArrayOutputStream (alternativley, create the
  PrintWriter with the boolean autoFlush set to reue, ie.
      java.io.PrintWriter pw = new java.io.PrintWriter(out, true);
*/
      // create a stream to accept the data
      java.io.PrintWriter pw = new java.io.PrintWriter(out);
      // write to the stream
      x.printStackTrace(pw);
      // make sure the stream is flushed
      pw.flush();
      // copy the data from the storage object
      String buff = out.toString();
      // cleanup
      pw.close();
      pw = null;
      out.reset();
      out = null;
      // print it
      System.out.println("Via String: " + buff);

      System.out.println("Direct to System.out:");
      x.printStackTrace(System.out);

    }
  }
}
 
0
 
LVL 6

Expert Comment

by:jpk041897
ID: 1233528
Hum? What do you want me to do with this code ? :-)
0
 
LVL 2

Author Comment

by:sprinkmeier
ID: 1233529
Just thought I'd give value for money to anyone who buys this question later.

0
 
LVL 6

Expert Comment

by:jpk041897
ID: 1233530
OH, Good Idea.
0

Featured Post

Master Your Team's Linux and Cloud Stack

Come see why top tech companies like Mailchimp and Media Temple use Linux Academy to build their employee training programs.

Question has a verified solution.

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

After being asked a question last year, I went into one of my moods where I did some research and code just for the fun and learning of it all.  Subsequently, from this journey, I put together this article on "Range Searching Using Visual Basic.NET …
Introduction This article is the first of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article explains our test automation goals. Then rationale is given for the tools we use to a…
Video by: Michael
Viewers learn about how to reduce the potential repetitiveness of coding in main by developing methods to perform specific tasks for their program. Additionally, objects are introduced for the purpose of learning how to call methods in Java. Define …
Viewers will learn one way to get user input in Java. Introduce the Scanner object: Declare the variable that stores the user input: An example prompting the user for input: Methods you need to invoke in order to properly get  user input:

777 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