java - 使用默认 Java Logging API 的 SimpleFormatter 的默认参数是什么？

Question

我想答案可能会有所不同，具体取决于所使用的处理程序，但假设使用了 ConsoleHandler 并使用了默认的 SimpleFormatter。传递给 SimpleFormatter.format() 的每个参数的数量、类型和可能的含义/语义是什么？

我在另一个 SO 问题中找到了这个字符串:

"%1\$tY-%1\$tm-%1\$td %1\$tH:%1\$tM:%1\$tS.%1\$tL %4\$s %2\$s %5\$s%6\$s%n"

(为 Groovy 添加了反斜杠)

注意缺少的 %3，那么这个参数是什么？还有 %7、%8 等等……它们是什么？

我想 %1 是当前时间，%4 是日志级别和其他几个...我正在寻找完整的参数列表和他们的意义/值(value)。

Answer 1

来自 http://docs.oracle.com/javase/7/docs/api/java/util/logging/SimpleFormatter.html

where the arguments are:
   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.

由于第一个参数是格式字符串，其余参数从索引 1 开始(日期在前):

in the format string:
   1 date - a Date object representing event time of the log record.
   2 source - a string representing the caller, if available; otherwise, the logger's name.
   3 logger - the logger's name.
   4 level - the log level.
   5 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.
   6 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.

(我无法相信我在发布到 SO 之前的初始搜索中找不到它 :-)