介绍了三种修改现有代码提高其可重用性的方法,它们分别是:改写类的实例方法,把参数类型改成接口,选择最简单的参数接口类型。-Introduce three types of modification of existing reusable code to improve their approach, they are: examples of types of methods adapted to changed interface parameter type, choose the simplest interface type parameters.