PS:静态与对象没关系
静态代码块在对象之前产生;若要初始化静态成员,则静态成员必须在静态代码块之前定义
总结:
直接分号结尾,没有花括号
接口:
接口特点:
package workhome.day04; public class interfaceDemo { public static void main(String[] args) { WomenStar ws = new WomenStar(); ws.white(); ws.rich(); TuHao tuhao = new TuHao(); tuhao.marry(ws); } } //定义接口 interface White{ public abstract void white(); } interface Rich{ public abstract void rich(); } interface Beauty{ public void beauty(); } interface WRB extends White,Rich,Beauty{ } //类实现接口 class WomenStar implements WRB{ public void white() { System.out.println("很白"); } public void rich() { System.out.println("有钱"); } @Override public void beauty() { // TODO Auto-generated method stub System.out.println("美"); } } class TuHao{ public void marry(WRB w) { w.white(); w.beauty(); w.rich(); } }
package workhome.day04; public class InterfaceDemo1 { public static void main(String[] args) { Jing8 jing8 = new Jing8(); jing8.cry(); Enter e = new Enter(); e.eat(jing8); } } abstract class Animal1{ abstract void cry(); } class Dog1 extends Animal implements Eatable{ void cry() { System.out.println("汪汪"); } public void eat() { System.out.println("吃"); } } class Jing8 extends Dog1 implements Pet{ public void cry() { System.err.println("jing6wuwu"); } @Override public void buy() { // TODO Auto-generated method stub System.out.println("买"); } } interface Eatable{ public void eat(); } interface Pet{ public void buy(); } class Enter{ public void eat(Eatable m) { System.out.println("食物就绪了"); m.eat(); } } class RichMan{ public void buy(Pet m) { m.buy(); } }
package workhome.day04; public class PolyDemo1 { public static void main(String[] args) { Dog d1 = new Dog(); d1.cry(); d1.watch(); Animal a1 = d1; a1.cry(); Animal a2 = new Dog(); Dog d2 = (Dog)a2; // Animal d2 = new Dog(); // d2.cry(); // // Object o1 = new Dog(); // o1.cry(); } } abstract class Animal{ abstract void cry(); } class Dog extends Animal{ public void cry() { System.out.println("www"); } public void watch() { System.out.println("看家"); } } class Cat extends Animal{ @Override void cry() { // TODO Auto-generated method stub System.out.println("miaomiao"); } }