2019-07-24 java 第二遍

java 的基本数据类型 primitive type

byte short int long

float double

char

boolean

继承和多态

关于继承

public class Fu {

    public String name = "fu";

    public void method()
    {
        System.out.println(name);
    }
    
}

public class Zi extends Fu{
    public String name="zi";

    @Override
    public void method() {
        System.out.println(name);
    }

    public void methodZi()
    {
        System.out.println(name);
    }
}

public static void main(String[] args) {
        Fu f = new Fu();
        Zi z = new Zi();
        Fu fz = new Zi();

        // 测试1  成员变量，谁调用，用谁的
        System.out.println(f.name); // fu
        System.out.println(z.name); // zi
        System.out.println(fz.name); // fu

        System.out.println("============================");
        //测试2 重载方法 方法属于谁，调用谁
        f.method();  // fu
        z.method();  // zi
        fz.method();  // zi
        z.methodZi();  //zi
        
        // 测试3 重载方法中调用父类的变量或者局部变量
        // this  super
}