Java 超详细讲解抽象类与接口的使用

//抽象类：被abstract修饰的类
public abstract class Shape{
   //抽象方法：被abstract修饰的方法，没有方法体
   public abstract void drew();
   //抽象类中也可以增加普通方法和属性
   public double getArea(){
      return area;
   }
}

public interface 接口名称{
    // 抽象方法
    public abstract void method1(); // public abstract 是固定搭配，可以不写
    public void method2();
    abstract void method3();
    void method4();
// 注意：在接口中上述写法都是抽象方法，
}

class Animal{
    protected String name;
    public Animal(String name){
        this.name=name;
    }
}
interface IFlying{
    void fly();
}
interface IRunning{
    void run();
}
interface ISwimming{
    void swim();
}
class Duck extends Animal implements IFlying,IRunning,ISwimming{
    public Duck(String name) {
        super(name);
    }
    @Override
    public void fly() {
        System.out.println("Duck正在飞！");
    }
    @Override
    public void run() {
        System.out.println("Duck正在跑！");
    }
    @Override
    public void swim() {
        System.out.println("Duck正在游泳！");
    }
}

interface Animal extends IRunning,IFlying{
    //……
} 

import java.util.Arrays;
class Student implements Comparable{
    private String name;
    private int age;
    public Student(String name,int age){
        this.name=name;
        this.age=age;
    }
    @Override  //重写toString方法
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
    @Override  //重写Comparable中的compareTo方法
    public int compareTo(Object o) {
        Student x=(Student)o;
        if(this.age>x.age){
            return -1;
        }if(this.age<x.age){
            return 1;
        }else{
            return 0;
        }
    }
}
public class TestDemo {
    public static void main(String[] args) {
        Student[] students=new Student[3];
        students[0]=new Student("zhangsan",18);
        students[1]=new Student("lisi",22);
        students[2]=new Student("liming",21);
        Arrays.sort(students);
        System.out.println(Arrays.toString(students));
    }
}

class Person implements Cloneable{
    private String name;
 
    public Person(String name) {
        this.name = name;
    }
 
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                '}';
    }
 
    @Override
    protected Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}
public class TestDemo1 {
    public static void main(String[] args) throws CloneNotSupportedException {
        Person person1=new Person("zhangsan");
        Person person2=(Person)person1.clone();
 
    }
}

//Object类中的equals方法
public boolean equals(Object obj){
    return (this==obj);//使用引用中的地址直接来比较
}