java中Implements和extends关键字的区别

下文笔者讲述Java开发中Implements和extends关键字的区别说明,如下所示

Implements和extends关键字的功能简介

extends:
   用于扩展一个类

implements:
   用于实现一个接口(interface)

Implements和extends关键字的区别

两者从功能上有着本质的区别
两者功能完全不同，这就是两者最大的区别

例：Implements和extends关键字的示例

 public interface ExampleInterface {
    public void doAction();
    public String doThis(int number);
 }

 public class sub implements ExampleInterface {
     public void doAction() {
       //specify what must happen
     }

     public String doThis(int number) {
       //specfiy what must happen
     }
 }


现在扩展一个类
 public class SuperClass {
    public int getNb() {
         //specify what must happen
        return 1;
     }

     public int getNb2() {
         //specify what must happen
        return 2;
     }
 }

 public class SubClass extends SuperClass {
      //you can override the implementation
      @Override
      public int getNb2() {
        return 3;
     }
 }
 

 //使用以上代码
  Subclass s = new SubClass();
  s.getNb(); //returns 1
  s.getNb2(); //returns 3

  SuperClass sup = new SuperClass();
  sup.getNb(); //returns 1
  sup.getNb2(); //returns 2