1.多态:在继承/实现情况下的一种现象,表现为对象多态(儿子,学生),行为多态(跑的快慢)
方法编译看左边,运行看右边
变量编译看左边,运行看左边
package com.itheima.多态;
public class Test {
//对象多态,行为多态
public static void main(String[] args) {
//1.对象多态
People p1=new Teacher();
p1.run();//行为多态 识别技巧:编译看左边,运行看右边
System.out.println(p1.name);
People p2=new Student();
p2.run();
System.out.println(p2.name);
}
}
class People{
public String name="父类People的名称";
public void run(){
System.out.println("人可以跑");
}
}
class Student extends People{
public String name="子类Student的名称";
@Override
public void run(){
System.out.println("跑的块");
}
}
class Teacher extends People{
public String name="子类Teacher的名称";
@Override
public void run(){
System.out.println("跑的气喘吁吁");
}
}
2.多态的好处:
package com.itheima.多态;public class Test {//多态好处public static void main(String[] args) {//好处1:实现解耦合,右边对象可以随时切换,后续业务随即改变People p1=new Teacher();p1.run();//好处2:可以使用父类类型的变量作为形参,可以接受一切子类对象Student student=new Student();Teacher teacher=new Teacher();go(student);go(teacher);//p1.teach();//报错,因为编译看左边,父类没有所以报错了 }//好处2:可以使用父类类型的变量作为形参,可以接受一切子类对象public static void go(People p){}}class People{public String name="父类People的名称";public void run(){System.out.println("人可以跑");}} class Student extends People{public String name="子类Student的名称";public void test(){System.out.println("考试");}@Overridepublic void run(){System.out.println("跑的块");} } class Teacher extends People{public String name="子类Teacher的名称";public void teach(){System.out.println("教书");}@Overridepublic void run(){System.out.println("跑的气喘吁吁");} }