访问控制符public、protected、friendly、protected的作用域

package com.scope;

public class Father {
	
	public int publicNumber =1;
	
	protected int protectedNumber = 2;
	
	int friendlyNumber =3;//默认的访问控制符为friendly
	
	private int privateNumber =4;
	
	public void printNumber(){
		System.out.println("publicNumber = "+publicNumber);
		System.out.println("protectedNumber = "+protectedNumber);
		System.out.println("friendlyNumber = "+friendlyNumber);
		System.out.println("privateNumber = "+privateNumber);
	}
	
}

package com.scope;

public class Son extends Father{

	public void printNumber(){
		System.out.println("publicNumber = "+publicNumber);
		System.out.println("protectedNumber = "+protectedNumber);
		System.out.println("friendlyNumber = "+friendlyNumber);
		System.out.println("privateNumber = "+privateNumber);//不能访问
	}
}

package com.scope1;

import com.scope.Father;

public class Daughter extends Father{
	
	public void printNumber(){
		System.out.println("publicNumber = "+publicNumber);
		System.out.println("protectedNumber = "+protectedNumber);
		System.out.println("friendlyNumber = "+friendlyNumber);//不能访问
		System.out.println("privateNumber = "+privateNumber);//不能访问
	}

}

package com.scope;

public class TestFather {
	
	Father father = new Father();
	
	public void printNumber(){
		System.out.println("publicNumber = "+father.publicNumber);
		System.out.println("protectedNumber = "+father.protectedNumber);
		System.out.println("friendlyNumber = "+father.friendlyNumber);
		System.out.println("privateNumber = "+father.privateNumber);//不能访问
	}

}

package com.scope1;

import com.scope.Father;

public class TestFather1 {
	Father father = new Father();
	
	public void printNumber(){
		System.out.println("publicNumber = "+father.publicNumber);
		System.out.println("protectedNumber = "+father.protectedNumber);//不能访问
		System.out.println("friendlyNumber = "+father.friendlyNumber);//不能访问
		System.out.println("privateNumber = "+father.privateNumber);//不能访问
	}
}

结论：
public 的作用域为：当前类、子类（同一个包中或不同包中皆可）、同一个包中的类、不同包中的类
protected的作用域为：当前类、子类（同一个包中或不同包中皆可）、同一个包中的类
friendly的作用域为：当前类、同一个包中的子类（不同包中的子类不能访问）
private的作用域为：当前类