java基础知识——类的继承

1.在子类中通过super调用父类的方法，并将该调用嵌入复写该方法的过程中

package learning;

class Super {
String nameString;
int age;
public Super(String name, int age) {
this.nameString = name;
this.age = age;
}
public void talk(){
System.out.print("姓名：" + nameString + "\t\t" + "年龄:" + age);
}
}
class Student extends Super{
String school;
public Student(){
super("张三", 25 );
}
//The method of Rewrite
public void talk(){
super.talk();
System.out.println("\t\t" + "学校:" + school);
}
}
/**
* The method of super()
* @author juefan
*/
public class Test1{
public static void main(String[] args){
Student student = new Student();
student.school = "华附";
student.talk();
}
}

2.了解接口与接口实现的简单应用例子

package learning;

interface Usb{
public void start();
public void stop();
}
class Mp3 implements Usb{
public void start(){
System.out.println("Mp3 start... ");
}
public void stop(){
System.out.println("Mp3 Stop...");
}
}
class CD implements Usb{
public void start(){
System.out.println("CD start...");
}
public void stop(){
System.out.println("CD stop...");
}
}
class Computer{
public void work(Usb usb){
usb.start();
usb.stop();
}
}
/**
* 以Usb类为接口类，Mp3跟CD都是Usb类的实现
* Computer类会有Usb接口作为参数，调用Usb接口的实现输出
* @author juefan
*
*/
public class TestInterface {
public static void main(String[] args){
Computer computer = new Computer();
computer.work(new Mp3());
computer.work(new CD());
}
}

可以看到Computer类中的work(Usb )方法是以Usb接口作为参数的

而Mp3跟CD都是Usb的接口的实现，这样就可以调用Mp3跟CD类中复写Usb接口中抽象方法的具体实现了，一个方法多种用处