Error：Implicit super constructor People() is undefined for default constructor. Must define an explicit constructor

當子類繼承父類的時候，若父類沒有定義帶參的構造方法，則子類可以繼承父類的預設構造方法

當父類中定義了帶參的構造方法，子類必須顯式的調用父類的構造方法

若此時，子類還想調用父類的預設構造方法，必須在父類中明確聲明預設的構造方法

 1 package com.gaohui;
 2 
 3 public class Test {
 4     public static void main(String [] args){
 5         Man man = new Man(24,"Tom");
 6         man.eat();
 7         man.eat("Tom");
 8         man.Exercise();
 9         Woman woman = new Woman();
10         
11     }
12     
13 }
14 
15 class People{
16     private int age;
17     private String name;
18     private String sex;
19     
20     public People(){
21         //如果父類沒有聲明預設的構造方法，子類繼承時必須顯式調用父類定義的構造方法
22     }
23     
24     public People(int age, String name){
25         System.out.println("構造方法一執行了！");
26     }
27     
28     public void eat(){
29         System.out.println("People need to eat!");
30     }
31     
32     public void eat(String name){
33         System.out.println(name+" needs to eat!");
34     }
35     
36     
37 }
38 
39 class Man extends People{
40     public  Man (int age, String name){//由於父類的構造方法是有參的，必須顯式調用父類的方法
41         super(age,name);
42     }
43     
44     public void Exercise(){
45         System.out.println("I love doing exercise!");
46     }
47 }
48 
49 
50 class Woman extends People{
51     
52 }