编写一个分数的类Fraction。此类包括两个整数型属性：分母和分子。定义该类构造方法及属性的存取方法。定义该类的化简方法，例如4/8化简为1/2。定义该类的toString方法，输出化简后的结果（如果是整数，则只输出整数）。-Writing a fraction of the class Fraction. This category includes two integer attributes: numerator and denominator. Define the class constructor and property access method. Defined such simplification methods, such as 1/2 4/8 simplification. ToString method defines the class, output the simplified result (if it is an integer, only the output integer).