想问问大伙JAVA中的多态。表现形式。
我看thinking in java3中的多态
People are often confused by other, non-object-oriented features of Java, like method overloading, which are sometimes presented as object-oriented. Don’t be fooled: If it isn’t late binding, it isn’t polymorphism这个是thingking in java3 中的的Summary中的一段。
但是4中好像没有。
望大牛帮忙解析下。
我看thinking in java3中的多态
People are often confused by other, non-object-oriented features of Java, like method overloading, which are sometimes presented as object-oriented. Don’t be fooled: If it isn’t late binding, it isn’t polymorphism这个是thingking in java3 中的的Summary中的一段。
但是4中好像没有。
望大牛帮忙解析下。
人们总是被java的另一种非面向对象的特性所困惑,就像方法重载,有时候它以面向对象而存在,请不要犯傻,如果没有后期绑定(也就是运行期的动态绑定),它就不是多态.所以,这段话要表达的意思就是3L所说的,多态要有动态绑定,否则就不是多态,方法重载也不是多态(因为方法重载是编译期决定好的,没有后期也就是运行期的动态绑定)
public class Address {
private String name;
public Address(String name){
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}定义基类(抽象类):
public abstract class Vehicle {
abstract void go(Address address);
}Car对于基类的实现:
public class Car extends Vehicle{
@Override
public void go(Address address){
System.out.println("Car to " + address.getName());
}
}Plane对于基类的实现:
public class Plane extends Vehicle{
@Override
void go(Address address) {
System.out.println("Plane to " + address.getName());
}
}
Driver中多态:
public void drive(Vehicle v){ ///多态,父类引用指向子类对象,实际传过来的是抽象类Vehicle的子类,或者实现类,然后编译器会根据具体实现类,来找实现方法。
v.go(new Address("杭州(abstract)")); ///此方法在具体的实现中被重写
}Test:
public static void main(String[] args) {
Driver d = new Driver();
d.drive(new Plane()); //实际是Plane对象,则编译器就会找到Plane中,对go的实现
d.drive(new Car()); //实际是Car对象,则编译器就会找到Plane中,对go的实现
}输出结果:
Plane to 杭州(abstract)
Car to 杭州(abstract)
public void eat() {
System.out.println("I'm eating, YamiYami!");
} public void eat(String food) {
System.out.println("I'm eating " + food + ", YamiYami!");
}
}
Override: 父类与子类的多态表现class Animal {
public void eat() {
System.out.println("Animal eating...");
}
}class Tiger extends Animal {
public void eat() {
System.out.println("Tiger eating...");
}
}Tiger中的eat方法是对Animal中eat方法的重写,也就是Override