多态在项目中的应用。
简单的例子
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
| package com.redisc;
import com.alibaba.fastjson.JSONObject;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.Transaction;
class Animal{
public String name = "anmail";
public void run(){
System.out.println(name + " run");
}
}
class Cat extends Animal{
public String name = "cat";
@Override
public void run() {
System.out.println(name + " cat run");
}
}
class Doge extends Animal{
public String name = "doge";
@Override
public void run() {
System.out.println(name + " doge run");
}
}
public class Test {
public static void main(String[] args) {
Animal animal = new Doge();
animal.run();
System.out.println(animal.name);
}
}
|
输出
其中
1
| Animal animal = new Doge();
|
就是多态的应用。
有一些细节
- 方法：编译看左边，运行看右边
- 变量：编译看左边，运行看左边
上面的输出已经说明了情况。
强制转换
因为，使用父类的话，不能使用自己特定行为，所以，要进行强制类型转换。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
| package com.redisc;
import com.alibaba.fastjson.JSONObject;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.Transaction;
class Animal {
public String name = "anmail";
public void run() {
System.out.println(name + " run");
}
}
class Cat extends Animal {
public String name = "cat";
@Override
public void run() {
System.out.println(name + " cat run");
}
}
class Doge extends Animal {
public String name = "doge";
@Override
public void run() {
System.out.println(name + " doge run");
}
public void dogeSkill() {
System.out.println("看家");
}
}
public class Test {
public static void main(String[] args) {
Animal animal = new Doge();
if (animal instanceof Doge) {
Doge doge = (Doge) animal;
doge.dogeSkill();
}
}
}
|
