Java compact1, compact2, compact3 java.util.logging Class SimpleFormatter（JDK8）

The formatting can be customized by specifying the format string in the java.util.logging.SimpleFormatter.format property. The given LogRecord will be formatted as if by calling:

    String.format(format, date, source, logger, level, message, thrown);
 

1. format - the java.util.Formatter format string specified in the java.util.logging.SimpleFormatter.format property or the default format.
2. date - a Date object representing event time of the log record.
3. source - a string representing the caller, if available; otherwise, the logger's name.
4. logger - the logger's name.
5. level - the log level.
6. message - the formatted log message returned from the Formatter.formatMessage(LogRecord) method. It uses java.text formatting and does not use the java.util.Formatter format argument.
7. thrown - a string representing the throwable associated with the log record and its backtrace beginning with a newline character, if any; otherwise, an empty string.

Some example formats:

• java.util.logging.SimpleFormatter.format="%4$s: %5$s [%1$tc]%n"

  This prints 1 line with the log level (4$), the log message (5$) and the timestamp (1$) in a square bracket.

       WARNING: warning message [Tue Mar 22 13:11:31 PDT 2011]
       

• java.util.logging.SimpleFormatter.format="%1$tc %2$s%n%4$s: %5$s%6$s%n"

  This prints 2 lines where the first line includes the timestamp (1$) and the source (2$); the second line includes the log level (4$) and the log message (5$) followed with the throwable and its backtrace (6$), if any:

       Tue Mar 22 13:11:31 PDT 2011 MyClass fatal
       SEVERE: several message with an exception
       java.lang.IllegalArgumentException: invalid argument
               at MyClass.mash(MyClass.java:9)
               at MyClass.crunch(MyClass.java:6)
               at MyClass.main(MyClass.java:3)
       

• java.util.logging.SimpleFormatter.format="%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS %1$Tp %2$s%n%4$s: %5$s%n"

  This prints 2 lines similar to the example above with a different date/time formatting and does not print the throwable and its backtrace:

       Mar 22, 2011 1:11:31 PM MyClass fatal
       SEVERE: several message with an exception
       

This method can also be overridden in a subclass. It is recommended to use the Formatter.formatMessage(java.util.logging.LogRecord) convenience method to localize and format the message field.