日誌記錄規範

有空再整理，先以下2篇文章

http://it.deepinmind.com/java/2014/02/27/%E6%89%93%E5%8D%B0%E6%97%A5%E5%BF%97%E7%9A%8410%E4%B8%AA%E5%BB%BA%E8%AE%AE.html

http://www.infoq.com/cn/articles/why-and-how-log