How do I get java logging output to appear on a single line?

JavaLogging

Java Problem Overview


At the moment a default entry looks something like this:

Oct 12, 2008 9:45:18 AM myClassInfoHere
INFO: MyLogMessageHere

How do I get it to do this?

Oct 12, 2008 9:45:18 AM myClassInfoHere - INFO: MyLogMessageHere

Clarification I'm using java.util.logging

Java Solutions


Solution 1 - Java

As of Java 7, java.util.logging.SimpleFormatter supports getting its format from a system property, so adding something like this to the JVM command line will cause it to print on one line:

-Djava.util.logging.SimpleFormatter.format='%1$tY-%1$tm-%1$td %1$tH:%1$tM:%1$tS %4$s %2$s %5$s%6$s%n'

Alternatively, you can also add this to your logger.properties:

java.util.logging.SimpleFormatter.format='%1$tY-%1$tm-%1$td %1$tH:%1$tM:%1$tS %4$s %2$s %5$s%6$s%n'

Solution 2 - Java

1) -Djava.util.logging.SimpleFormatter.format

Java 7 supports a property with the java.util.Formatter format string syntax.

-Djava.util.logging.SimpleFormatter.format=... 

See here.

My favorite is:

-Djava.util.logging.SimpleFormatter.format=%1$tY-%1$tm-%1$td %1$tH:%1$tM:%1$tS %4$-6s %2$s %5$s%6$s%n

which makes output like:

2014-09-02 16:44:57 SEVERE org.jboss.windup.util.ZipUtil unzip: Failed to load: foo.zip

2) Putting it to IDEs

IDEs typically let you set system properties for a project. E.g. in NetBeans, instead of adding -D...=... somewhere, add the property in the action dialog, in a form of java.util.logging.SimpleFormatter.format=%1$tY-%1$tm-... - without any quotes. The IDE should figure out.

3) Putting that to Maven - Surefire

For your convenience, Here is how to put it to Surefire:

<!-- Surefire -->
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.17</version>
    <configuration>
        <systemPropertyVariables>
            <!-- Set JUL Formatting -->
            <java.util.logging.SimpleFormatter.format>%1$tY-%1$tm-%1$td %1$tH:%1$tM:%1$tS %4$-6s %2$s %5$s%6$s%n</java.util.logging.SimpleFormatter.format>
        </systemPropertyVariables>
    </configuration>
</plugin>

4) Hand-made

I have a library with few java.util.logging related classes. Amongst them, it's SingleLineFormatter. Downloadable jar here.

public class SingleLineFormatter extends Formatter {

  Date dat = new Date();
  private final static String format = "{0,date} {0,time}";
  private MessageFormat formatter;
  private Object args[] = new Object[1];

  // Line separator string.  This is the value of the line.separator
  // property at the moment that the SimpleFormatter was created.
  //private String lineSeparator = (String) java.security.AccessController.doPrivileged(
  //        new sun.security.action.GetPropertyAction("line.separator"));
  private String lineSeparator = "\n";

  /**
   * Format the given LogRecord.
   * @param record the log record to be formatted.
   * @return a formatted log record
   */
  public synchronized String format(LogRecord record) {

    StringBuilder sb = new StringBuilder();

    // Minimize memory allocations here.
    dat.setTime(record.getMillis());    
    args[0] = dat;


    // Date and time 
    StringBuffer text = new StringBuffer();
    if (formatter == null) {
      formatter = new MessageFormat(format);
    }
    formatter.format(args, text, null);
    sb.append(text);
    sb.append(" ");


    // Class name 
    if (record.getSourceClassName() != null) {
      sb.append(record.getSourceClassName());
    } else {
      sb.append(record.getLoggerName());
    }

    // Method name 
    if (record.getSourceMethodName() != null) {
      sb.append(" ");
      sb.append(record.getSourceMethodName());
    }
    sb.append(" - "); // lineSeparator



    String message = formatMessage(record);

    // Level
    sb.append(record.getLevel().getLocalizedName());
    sb.append(": ");

    // Indent - the more serious, the more indented.
    //sb.append( String.format("% ""s") );
    int iOffset = (1000 - record.getLevel().intValue()) / 100;
    for( int i = 0; i < iOffset;  i++ ){
      sb.append(" ");
    }


    sb.append(message);
    sb.append(lineSeparator);
    if (record.getThrown() != null) {
      try {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        record.getThrown().printStackTrace(pw);
        pw.close();
        sb.append(sw.toString());
      } catch (Exception ex) {
      }
    }
    return sb.toString();
  }
}

Solution 3 - Java

Similar to Tervor, But I like to change the property on runtime.

Note that this need to be set before the first SimpleFormatter is created - as was written in the comments.

	System.setProperty("java.util.logging.SimpleFormatter.format", 
			"%1$tF %1$tT %4$s %2$s %5$s%6$s%n");

Solution 4 - Java

Like Obediah Stane said, it's necessary to create your own format method. But I would change a few things:

  • Create a subclass directly derived from Formatter, not from SimpleFormatter. The SimpleFormatter has nothing to add anymore.

  • Be careful with creating a new Date object! You should make sure to represent the date of the LogRecord. When creating a new Date with the default constructor, it will represent the date and time the Formatter processes the LogRecord, not the date that the LogRecord was created.

The following class can be used as formatter in a Handler, which in turn can be added to the Logger. Note that it ignores all class and method information available in the LogRecord.

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Date;
import java.util.logging.Formatter;
import java.util.logging.LogRecord;

public final class LogFormatter extends Formatter {

    private static final String LINE_SEPARATOR = System.getProperty("line.separator");

    @Override
    public String format(LogRecord record) {
        StringBuilder sb = new StringBuilder();

        sb.append(new Date(record.getMillis()))
            .append(" ")
            .append(record.getLevel().getLocalizedName())
            .append(": ")
            .append(formatMessage(record))
            .append(LINE_SEPARATOR);
        
        if (record.getThrown() != null) {
            try {
                StringWriter sw = new StringWriter();
                PrintWriter pw = new PrintWriter(sw);
                record.getThrown().printStackTrace(pw);
                pw.close();
                sb.append(sw.toString());
            } catch (Exception ex) {
                // ignore
            }
        }

        return sb.toString();
    }
}

Solution 5 - Java

This is what I'm using.

public class VerySimpleFormatter extends Formatter {

    private static final String PATTERN = "yyyy-MM-dd'T'HH:mm:ss.SSSXXX";

    @Override
    public String format(final LogRecord record) {
        return String.format(
                "%1$s %2$-7s %3$s\n",
                new SimpleDateFormat(PATTERN).format(
                        new Date(record.getMillis())),
                record.getLevel().getName(), formatMessage(record));
    }
}

You'll get something like...

2016-08-19T17:43:14.295+09:00 INFO    Hey~
2016-08-19T17:43:16.068+09:00 SEVERE  Seriously?
2016-08-19T17:43:16.068+09:00 WARNING I'm warning you!!!

Solution 6 - Java

Eclipse config

Per screenshot, in Eclipse select "run as" then "Run Configurations..." and add the answer from Trevor Robinson with double quotes instead of quotes. If you miss the double quotes you'll get "could not find or load main class" errors.

Solution 7 - Java

I've figured out a way that works. You can subclass SimpleFormatter and override the format method

	public String format(LogRecord record) {
		return new java.util.Date() + " " + record.getLevel() + " " + record.getMessage() + "\r\n";
	}

A bit surprised at this API I would have thought that more functionality/flexibility would have been provided out of the box

Solution 8 - Java

If you log in a web application using tomcat add:

-Djava.util.logging.ConsoleHandler.formatter = org.apache.juli.OneLineFormatter

On VM arguments

Solution 9 - Java

This logging is specific to your application and not a general Java feature. What application(s) are you running?

It might be that this is coming from a specific logging library that you are using within your own code. If so, please post the details of which one you are using.

Solution 10 - Java

if you're using java.util.logging, then there is a configuration file that is doing this to log contents (unless you're using programmatic configuration). So, your options are

  1. run post -processor that removes the line breaks
  2. change the log configuration AND remove the line breaks from it. Restart your application (server) and you should be good.

Attributions

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionObediah StaneView Question on Stackoverflow
Solution 1 - JavaTrevor RobinsonView Answer on Stackoverflow
Solution 2 - JavaOndra ŽižkaView Answer on Stackoverflow
Solution 3 - JavaGuy LView Answer on Stackoverflow
Solution 4 - JavaBenno RichtersView Answer on Stackoverflow
Solution 5 - JavaJin KwonView Answer on Stackoverflow
Solution 6 - JavarupwebView Answer on Stackoverflow
Solution 7 - JavaObediah StaneView Answer on Stackoverflow
Solution 8 - JavaMohammad IrfanView Answer on Stackoverflow
Solution 9 - JavaLeigh CaldwellView Answer on Stackoverflow
Solution 10 - JavaanjanbView Answer on Stackoverflow