java学习笔记6：构造方法、对象的创建、继承、重写、static、final关键字

思维导图

一、构造方法举例

    public class MyTest {
        public static void main(String[] args) {
            //采用无参构造给成员变量设值
            Teacher teacher = new Teacher();
            teacher.setName("刘亦菲");
            teacher.setAge(19);
            System.out.println(teacher.getName()+"---"+teacher.getAge());
            System.out.println("-------------------------");
            //采用有参构造给成员变量设值
            Teacher teacher1 = new Teacher("林青霞", 28);
            System.out.println(teacher1.getName()+"==="+teacher1.getAge());
        }
    }
class Teacher {
        private String name;
        private int age;
        //提供无参构造   
        public Teacher() {
        }
        //提供有参构造
        public Teacher(String name, int age) {
            this.name = name;
            this.age = age;
        }   
        //提供get set 方法 
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }    
        public int getAge() {
            return age;
        }    
        public void setAge(int age) {
            this.age = age;
        }
    }

二、对象创建内存图

三、继承与重新举例

public class MyTest {
    public static void main(String[] args) {
        Dog dog = new Dog();
        dog.name="旺财";
        dog.age=12;
        System.out.println(dog.name+"==="+dog.age);
        dog.eat();
        dog.sleep();
        System.out.println("-----------");
        Cat cat = new Cat();
        cat.name="汤姆";
        cat.age=3;
        System.out.println(cat.name+"==="+cat.age);
        cat.eat();
        cat.sleep()；
        }
    }
    class Animal {
       public String name;
       public int age;
       public void eat() {
       System.out.println("吃饭饭");
       }
       public void sleep() {
        System.out.println("睡觉觉");
       }
  }
    class Cat extends Animal {
      @Override
      public void eat() {
         System.out.println("猫吃鱼");
      }
      @Override
      public void sleep() {
          System.out.println("猫爱白天睡觉");
      }

       public void catchMouse() {
       System.out.println("猫抓老鼠");
     }
}
    class Dog extends Animal{
        @Override
        public void eat() {
          super.eat();
          System.out.println("狗吃完饭，再撒个欢");
        }
        @Override
        public void sleep() {
           super.sleep();
           System.out.println("睡起来去约会");
        }
       public void lookDoor() {
       System.out.println("狗看门");
      }
 }

四、static关键字的内存