Formatting Logger File Handler Issue

Question

I am following this guide to output Logger info to a File with a formatted FileHandler.

public class TestLog {

public static Logger logger;

static {
try {
  boolean append = true;
  FileHandler fh = new FileHandler("TestLog.log", append);
  fh.setFormatter(new Formatter() {
     public String format(LogRecord rec) {
        StringBuffer buf = new StringBuffer(1000);
        buf.append(new java.util.Date());
        buf.append(' ');
        buf.append(rec.getLevel());
        buf.append(' ');
        buf.append(formatMessage(rec));
        buf.append('\n');
        return buf.toString();
        }
      });
  logger = Logger.getLogger("TestLog");
  logger.addHandler(fh);
}
catch (IOException e) {
  e.printStackTrace();
}
}

The guide shows the output will print each new logger message on a new line,

Mon Feb 28 21:30:54 EST 2005 SEVERE my severe message
Mon Feb 28 21:30:54 EST 2005 WARNING my warning message
Mon Feb 28 21:30:54 EST 2005 INFO my info message

However, no new line is being appended in the file, or they are on the StringBuffer and then a new one is created and it is lost somehow. Can someone explain the issue here? Thanks.

My method/logger are not static, could this be causing the problem?

What issue you are trying to solve? Output what you what you want to achieve, its default features of logging framework, what you need to set *pattern* of output. — Subhrajyoti Majumder, Jun 25 '13 at 14:14
New lines are not being appended in the file, everything is on one line. This is an issue for readability. — PandaBearSoup, Jun 25 '13 at 14:15

score 2 · Accepted Answer · answered Jun 25 '13 at 14:34

I was able to solve the problem. The tutorial constructs the formatter as such,

 fh.setFormatter(new Formatter() {
 public String format(LogRecord rec) {
    StringBuffer buf = new StringBuffer(1000);
    buf.append(new java.util.Date());
    buf.append(' ');
    buf.append(rec.getLevel());
    buf.append(' ');
    buf.append(formatMessage(rec));
    buf.append('\n');
    return buf.toString();
    }
  });

The problem is that this does not actually append a new line in the file, instead of using

buf.append('\n');

you need to use

buf.append(System.getProperty("line.separator"));

My file now is readable, not a mess of connected lines. Hope this helps someone in the future.

score 1 · Answer 2 · answered Jun 25 '13 at 14:18

1

Filehandler Tutorial

This tutorial show that you have to flush and then close the Handler after adding the Message.

answered Jun 25 '13 at 14:18

Zeh

186
2
8

I flush the handler after each time I log, and close the handler before closing the application. – PandaBearSoup Jun 25 '13 at 14:24
I am sorry, I completely misunderstood your question. I thought no line was added to the text at all, not only new lines. Nice job finding the answer, though! – Zeh Jun 25 '13 at 14:41

Formatting Logger File Handler Issue

2 Answers2