JAVA笔记2__类/封闭性/构造方法/方法的重载/匿名对象

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);
}
}