说明：  UML（统一建模语言）是一个绘制软件概念图的图形化记法(notation)。人们可以用它绘制图形，用这些图形来表示一个计划进行的软件设计的问题域，或者用这些图来表示一个已经完成的软件实现。Fowler（译者注：著名IT 技术作家）描述它们时分成了三种不同的层次：概念层（Conceptual）、规格说明层（Specification）和实现层（Implementation），我们将细述后面两种。
(UML (Unified Modeling Language) is a concept mapping software graphical map Hutchison (notation). People can use it drawing, use of graphics to show a plan for the software design, the problem domain, or the use of these maps to show a completed software implementation. Fowler (Translator's Note : IT famous writer) to describe their hours into three different levels : the concept of layers (Conceptual) layer specifications (Specification), and Layer (Implementation), we are going to be two behind.)