weixin_44892460的博客

//饿汉式(静态常量) class Singleton { //1. 构造器私有化, 外部能new private Singleton() { } //2.本类内部创建对象实例 private final static Singleton instance = new Singleton(); //3. 提供一个公有的静态方法，返回实例对象 public static Singleton getInstance() { return instance; } //..

类图 代码实现 //被适配的类 public class Voltage220V { //输出220V的电压 public int output220V() { int src = 220; System.out.println("电压=" + src + "伏"); return src; } } //适配接口 public interface IVoltage5V { public int output5V(); } //适配器类 public class Volta...

问题 代码 public abstract class Duck { public Duck() { } public abstract void display();//显示鸭子信息 public void quack() { System.out.println("鸭子嘎嘎叫~~"); } public void swim() { System.out.println("鸭子会游泳~~"); } public void fly() { System..