public class _01staticDemo {
	
	
	public static void main(String[] args) {
		
		
		User zs = new User(10,"zs");
		User ls = new User(20,"ls");
		
		
		//static
		   //含义:类级别
		   //修饰
		       //成员变量
		           //含义:类级别的成员变量
		           //特点
		              //多个对象共享一份(只有一份)
		              //类点.调用 || 对象.调用(不建议)
		       //方法
		   //注意事项??
		
		
		
		User.blood="red";
		System.out.println(User.blood);
		
		
		System.out.println(zs.blood);
		System.out.println(ls.blood);
		
		zs.blood="blue";
		
		System.out.println(zs.blood);
		System.out.println(ls.blood);
		
		System.out.println(User.blood);
	}

}


class User{
	
	int age;
	String name;
	
	static String blood;
	   //类级别 
	   //特点
	       //所有该类创建的对象共享一份【只有一份】
	       //类.即可
	       
	
	public User(int age,String name){
		this.age = age;
		this.name = name;
	}
	
}

/**
 * 工具类
 * @author Administrator
 *
 */
public class CommonUtil{
	
	
	/**
	 * 冒泡排序
	 * @param data
	 */
	public static void sort(int [] data){
		for(int i=1;i<data.length;i++){
			System.out.println(i);
			for(int j=0;j<data.length-i;j++){
				if(data[j]>data[j+1]){
					 int temp = data[j];
					 data[j] = data[j+1];
					 data[j+1] = temp;
				}
			}
		}
	}	
}

public class _02staticMethod {
	//static
	   //修饰
	       //成员变量
	       //方法
	           //目的:一般作为工具类
	           //调用方式:类名.static修饰的方法   || 对象.static修饰的方法[不建议]
	public static void main(String[] args) {
		 
		int [] xx = {1,2,7,5};
		 
		CommonUtil.sort(xx);
		
		//CommonUtil util = new CommonUtil();
		//util.sort(xx);
		
		System.out.println(Arrays.toString(xx));
	}
}

public class _03GC {
	
	public static void main(String[] args) {
		 
        //没有被引用
		//Teacher teacher = new Teacher("ZS");
		//teacher=null;
		//System.gc();
		
        //理解对象,使用完之后就变成孤立对象
		//new Teacher("ZS");
		//System.gc();
		
		
        //超出对应的作用范围也会被回收
		for(int i=0;i<4;i++){
			Teacher teacher = new Teacher("zs"+i);
		}
	  
        //手动执行一次回收工作
		System.gc();
	}

}


class Teacher{ 
	 
	String name;
	
	public Teacher(String name){
		this.name = name;
	}
	
	
	@Override
	protected void finalize() throws Throwable {
		 System.out.println(name+"被回收了");
	}	
}

public class _04ObjectComparate {
	
	
	public static void main(String[] args) {
		
		
		Car one = new Car(110);
		Car two = new Car(110);
		
		System.out.println(one == two);
		 
		//instanceOf
		
		System.out.println(one instanceof Car);
		System.out.println(two instanceof Car);
		
		System.out.println(two instanceof Object);
		
		
		
	}

}

class Car{
	
	int num;
	Car(int num){
		this.num = num;
	} 
}

范围修饰符 类名([数据类型 参数1,...,数据类型 参数N]){
    [调用其他构造器]
    初始化成员变量;
}

当前类的范围修饰符 类名(){
    
}

public class _05DefaultConstructor {
	
	public static void main(String[] args) {
		
		Dog dog = new Dog("xx");
	}
}


 class Dog {
	String name;
	Dog(String name){
		this.name = name;
	}
}

//子类(派生类) extends 父类{
    //0-N个扩展属性
    //0-N个扩展方法
//}

public class Animal {
	
	String name;
	int age;
	
	public void eat(){
		System.out.println("吃东西");
	}
}

public class Cat extends Animal {
	 
	String color;
	 
	public void catchFish(){
		System.out.println("捕鱼");
	}
}

public class Dog extends Animal{
	 
}

public class Animal {
	
	String name;
	int age;
	
	public void eat(){
		System.out.println("吃东西");
	}
}

public class Cat extends Animal {
	 
	String color;
	 
	public void catchFish(){
		System.out.println("捕鱼");
	}
}

package com.neu.day04._02extends;

public class Dog extends Animal{
	 
}

public class Test {
	
	public static void main(String[] args) {
		
		Dog dog = new Dog();
		dog.name = "土狗";
		dog.age = 10;
		
		Cat cat = new Cat();
		cat.name="小猫";
		cat.age = 20;
		cat.color="白色";
		
		
		dog.eat();
		
		 
		//dog 是   animal 
		Animal animal = cat;
		
		if(animal instanceof Dog){
			 Dog otherDog =  (Dog) animal;
			 System.out.println("dog...");
		}else if(animal instanceof Cat){
			Cat otherCat =(Cat) animal; //ClassCastException
			System.out.println("cat...");
		}
	}
}

public class Test {
	
	public static void main(String[] args) {
		User user = new User();
		
		user.setAge(10);
		user.setName("xx");
		
		user.sayInfo();	
	}
}

public class User {
	
	private String name;
	private int age;
	
	
	//一般做法
	   //字段
	      //全部private
	      //对外提供setter || getter的方法 【eclipse生成】
       //方法
          //如果方法确定只在本类中使用,直接使用private即可【总结:作用范围越小越好】
	

	public void setName(String name) {
		this.name = name;
	}
	
	
	public void setAge(int age) {
		this.age = age;
	}
	
	public void sayInfo(){
		System.out.println("我的年龄是"+age+"名字是"+name);
	}
}

public class User {
	
    protected String name="xx";
    protected int age;
    
    public void say(){
    	System.out.println("hello");
    }
}

public class Worker extends User{
	
	String name="yy";
	 
	//supper
	   //含义:父对象
	   //使用场景
	       //调用父类的构造器[TODO]
	
	       //调用父对象的字段
	       //调用父对象的方法

	public void print(){
		//System.out.println(name);
		System.out.println(super.name);
	}
	 
	public void say(){
	    System.out.println("world");
	}
	 
	 public void sayInfo(){
		 //say();
		 super.say();
	 }
	
	public static void main(String[] args) {
		Worker worker = new Worker();
		//worker.print();
		worker.sayInfo();
	}
}

@Overried
修饰符 方法返回类型 方法名([参数1,参数2,参数3…]){ //[]:代表可有可无
    //新的实现过程…… 
}

public class Animal {
	
	protected String name;
	
	protected void move(){
		System.out.println("脚....");
	}
}

public class Bird extends Animal{
	
	//重写父类的方法
	   
	//语法
	    //@Override
	    //就是一个和父类一样的方法,只是方法体不一样
	
	//@Override 注解
	
	//注意点
	   //返回的范围修饰符要大于等于父类方法的
	   //不能抛出比父类更大的异常
	   //static是不能重写
	   
	
	public static void main(String[] args) {
		
		Bird bird = new Bird();
		bird.name="小鸟";
		
		
		//bird.move();
		
		
	}

	//代表该方法是重写父类的[强烈建议]
	@Override
	public void move() {
		System.out.println("翅膀飞行");
	}
}