JAVA

面向对象的多态实现
package duotaixing;

public class next {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        next a=new next();
        a.put(new zoo());
        a.put(new dog());
        a.put(new cat());
    }
    public void put(zoo a){///可以从子类到父类的识别
        a.eat();
        a.sleep();
        if(a instanceof dog) {///如果long转化int一般
            dog b=(dog)a;
            b.good();
        }
        if(a instanceof cat) {
            cat b=(cat)a;
            b.good();
        }
    }

}
class zoo{
    String name;
    int age;
    public void eat() {
        System.out.println("动物进食");
    }
    public void sleep() {
        System.out.println("动物睡觉");
    }
}
class dog extends zoo{///继承父类的属性
    public void eat() {
        System.out.println("狗进食");
    }
    public void sleep() {
        System.out.println("狗睡觉");
    }
    public void good() {
        System.out.println("狗会看家");
    }
}
class cat extends zoo{
    public void eat() {
        System.out.println("猫进食");
    }
    public void sleep() {
        System.out.println("猫睡觉");
    }
    public void good() {
        System.out.println("猫会看家");
    }
}

动物进食

动物睡觉

狗进食
狗睡觉
狗会看家
猫进食
猫睡觉
猫会看家

包装类的使用
package nie;

import org.junit.Test;

public class leixing {

    @Test
    public void test1() {
        int a1=10;
        String str1=a1+"";
        Integer a2=a1;
        String str2=String.valueOf(a2);///基本类型----》String类。。调用String类的重载valueOf
        String str3=String.valueOf(true);
        System.out.println(a2);
        System.out.println(str1);
        System.out.println(str2);
        System.out.println(str3);
        int a3= Integer.parseInt(str2);///同上   相反
        System.out.println(a3);
        boolean b=Boolean.parseBoolean(str3);
        System.out.println(b);
    }
}

10
10
10
true
10
true