[20-04-23][Self-study Notes 9]Java Array of Objects

Posted 2021-02-27 mirai3usi9

对象数组：一组相关的对象，使用时要先开辟空间，此时数组里每一个对象都是null值，使用时数组中的每一个对象必须分别进行实例化。

 

 1 package tryprj;
 2 
 3 public class Temp {
 4 
 5     public static void main(String[] args) {
 6 
 7         /** 声明一个对象数组，包含三个对象 */
 8         System.out.println("---动态初始化---");
 9         
10         Person[] person = new Person[3];
11 
12         for (int x = 0; x < person.length; x++) {
13             System.out.println(person[x] + " ");
14         }
15 
16         /** 创建三个对象并实例化 */
17         Person p1 = new Person("熊大", 1);
18         Person p2 = new Person("熊二", 2);
19         Person p3 = new Person("萌萌", 3);
20 
21         person[0] = p1;
22         person[1] = p2;
23         person[2] = p3;
24         
25         for (int x = 0; x < person.length; x++) {
26             System.out.println(person[x] + " ");
27         }
28         
29         System.out.println("---静态初始化---");
30 
31         Person[] person2 = { new Person("熊大", 1), new Person("熊二", 2), new Person("萌萌", 3) };
32         
33         for (int x = 0; x < person2.length; x++) {
34             System.out.println(person2[x] + " ");
35         }
36         
37     }
38 
39 }
40 
41 class Person {
42 
43     /** 姓名年龄属性 */
44     private String name;
45     private int age;
46 
47     /** 构造方法赋值 */
48     public Person(String name, int age) {
49 
50         this.name = name;
51         this.age = age;
52     }
53 
54     public String toString() {
55 
56         return "[name=" + name + ", age=" + age + "]";
57     }
58 }

 

结果如下：

---动态初始化---
null
null
null
[name=熊大, age=1]
[name=熊二, age=2]
[name=萌萌, age=3]
---静态初始化---
[name=熊大, age=1]
[name=熊二, age=2]
[name=萌萌, age=3]