Java继承
Java inheritance
我们可以把继承看成是儿子，继承了父亲的一些特点，但是儿子可以有一些改变。
java里儿子继承了父亲的公共属性 和公共方法，儿子可以修改这些属性和方法。儿子修改父亲的公共属性，我们叫重载。没有修改的叫继承。
We can think of that their children inherit their father, the child can have the father of all public properties and public methods, you can also change these properties and methods. When the children change his father's property, we call it overide. Does not change is called inheritance.
下面看一个汽车和蓝色汽车的例子。
father class
/**
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*/
import java.util.*;
public class Car // Car is a class
{
public int wheel = 4; // wheel,car's property
public void run(){ // a method , car can run
System.out.println("car run");
}
public void stop(){ // a method , car can run
System.out.println("car stop");
}
public static void main(String[] args){
Car c1 = new Car(); //a new object
c1.run();
Car c2 = new Car();// second object
c2.stop();
//there are two car
// first run, second stop.
/*
Car is a class, c1 is an Object,c2 is other Object.
*/
}
}
child class
/**
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learn java is so easy
*/
import java.util.*;
public class BlueCar extends Car// Car is a father class,Blue Car is a child class.
{
public void MYColor(){
System.out.println("my color is blue");
}
public void stop(){ // overide
System.out.println("I can stop!");
}
public static void main(String[] args){
BlueCar c1 = new BlueCar(); //a new object
c1.run(); // child has father's method and property
System.out.println("c1 wheel is " + c1.wheel);
c1.stop(); // child can change the method what father has. we call it overide in java.
c1.MYColor(); // child has same method what father has not
}
}