在Java中如何继承类
继承是面向对象的编程概念之一。这个概念允许类从其他类继承常用的状态和行为。继承是将常用状态和行为放入一个类并重用它的方法。
从其他类继承所有属性的类称为子类。而继承的类称为超类。您可以extends在类定义中使用关键字来继承其他类。
当您将final关键字应用于类声明时，您将使该类成为最终类，而其他类不能扩展最终类。
例如，下面有一个Truck类和一个Sedan从Car类派生的。
package org.nhooo.example.fundamental;public class CarDemo {
public static void main(String[] args) {
Car car = new Car();
car.setBrand("Honda");
System.out.println("Brand = " + car.getBrand());
// setBrand()和getBrand()继承自Car
// 类。
Truck truck = new Truck();
truck.setBrand("Ford");
System.out.println("Brand = " + truck.getBrand());
truck.getLoadCapacity();
// setBrand()，getBrand()和setNumberOfSeat方法
// 是从Car类继承的。
Sedan sedan = new Sedan();
sedan.setBrand("Hyundai");
System.out.println("Brand = " + sedan.getBrand());
sedan.setNumberOfSeat(2);
sedan.getGearType();
}
}
在这里Car，，Truck和Sedan类的定义。
package org.nhooo.example.fundamental;public class Car {
private String type;
private String brand;
private String model;
private int numberOfSeat;
public Car() {
}
public Car(String type, String brand, String model) {
this.type = type;
this.brand = brand;
this.model = model;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
public String getModel() {
return model;
}
public void setModel(String model) {
this.model = model;
}
public int getNumberOfSeat() {
return numberOfSeat;
}
public void setNumberOfSeat(int numberOfSeat) {
this.numberOfSeat = numberOfSeat;
}
public String getCarInfo() {
return "Type: " + type
+ "; Brand: " + brand
+ "; Model: " + model;
}
}
package org.nhooo.example.fundamental;public class Truck extends Car {
private int loadCapacity;
public Truck() {
}
public Truck(String type, String brand, String model) {
super(type, brand, model);
}
public int getLoadCapacity() {
return loadCapacity;
}
public void setLoadCapacity(int loadCapacity) {
this.loadCapacity = loadCapacity;
}
@Override
public String getCarInfo() {
return "Type: " + getType()
+ "; Brand: " + getBrand()
+ "; Model: " + getModel()
+ "; Load capacity: " + getLoadCapacity();
}
}
package org.nhooo.example.fundamental;public class Sedan extends Car {
private int gearType;
public Sedan() {
}
public int getGearType() {
return gearType;
}
public void setGearType(int gearType) {
this.gearType = gearType;
}
}
以上是 在Java中如何继承类 的全部内容， 来源链接： utcz.com/z/348729.html
