public class Main { public static void main(String[] args) { Chicken c1 = new Chicken(); Chicken c2 = null; c1.eat(); System.out.println(c1.age); c2 = c1; c2.eat(); } } class Chicken{ int color; char sex; int age; void eat(){ System.out.println("chikcen1 eat rice."); } }
public class Main { public static void main(String[] args) { Person p1 = new Person(); p1.setName("dining"); System.out.println(p1.getName()); } } /** * 封闭性 * 1.把属性设成私有 * 2.为属性提供get/set方法 */ class Person{ private String name; private int age; public void setName(String name){ this.name = name; } public String getName(){ return name; } }
public class Main { public static void main(String[] args) { Duck p1 = new Duck("fishDining"); System.out.println(p1.getName()); Duck p2 = new Duck("fishDining2",20); System.out.println(p2.getName()+" "+p2.getAge()); } } /** * 构造方法 * 1.默认(无参)构造方法:public Duck(){} * 2.带一个(多个)参数的构造方法:Public Duck(String name){this.name=name;} */ class Duck{ private String name; private int age; //默认构造方法 public Duck(){} public Duck(String name,int age){ this.name = name; this.age = age; } public Duck(String name){ this.name = name; System.out.println("I‘m a duck."); } public void setName(String name){ this.name = name; } public String getName(){ return name; } public void setAge(int age){ this.age = age; } public int getAge(){ return age; } }
public class Main { public static void main(String[] args) { Woman w1 = new Woman(); w1.aa(); w1.aa("keke1"); w1.aa("keke1",21); } } /** * 方法的重载(方法具有相同名字,但具有不同的参数和不同的定义) */ class Woman{ public String name; public int age; public void aa(){ System.out.println("aa1"); } public void aa(String name){ System.out.println("aa2:"+name); } public void aa(String name,int age){ System.out.println("aa2:"+name+":"+age); } }
import java.util.Random; import java.util.Scanner; public class Main { public static void main(String[] args) { new Woman().aa(); //生成一个匿名对象 new Woman().aa("loveu1"); } } /** * 匿名对象:定义一个没有名称的对象,特点:只能使用一次(直接在堆中开辟内存空间,使用后成为垃圾对象,被GC回收) */ class Woman{ public String name; public int age; public void aa(){ System.out.println("aa1"); } public void aa(String name){ System.out.println("aa2:"+name); } public void aa(String name,int age){ System.out.println("aa2:"+name+":"+age); } }
时间: 2024-10-15 21:48:42