From b9ea2c1322c9bbe38c432a5eced458b6626e63c5 Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Mon, 27 Jul 2026 15:57:00 +0800
Subject: [PATCH] =?UTF-8?q?day10-=E5=AF=B9=E8=B1=A1=E7=9A=84=E5=90=91?=
 =?UTF-8?q?=E4=B8=8A=E5=90=91=E4=B8=8B=E8=BD=AC=E5=9E=8B=E4=BB=A3=E7=A0=81?=
 =?UTF-8?q?=E5=AE=9E=E7=8E=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../com/inmind/duotai_member09/Demo09.java    |  4 ++++
 .../src/com/inmind/object_cast10/Animal.java  |  5 +++++
 day10/src/com/inmind/object_cast10/Cat.java   | 11 ++++++++++
 .../src/com/inmind/object_cast10/Demo10.java  | 21 +++++++++++++++++++
 day10/src/com/inmind/object_cast10/Dog.java   | 12 +++++++++++
 5 files changed, 53 insertions(+)
 create mode 100644 day10/src/com/inmind/object_cast10/Animal.java
 create mode 100644 day10/src/com/inmind/object_cast10/Cat.java
 create mode 100644 day10/src/com/inmind/object_cast10/Demo10.java
 create mode 100644 day10/src/com/inmind/object_cast10/Dog.java

diff --git a/day10/src/com/inmind/duotai_member09/Demo09.java b/day10/src/com/inmind/duotai_member09/Demo09.java
index 1de814b..b82f3b0 100644
--- a/day10/src/com/inmind/duotai_member09/Demo09.java
+++ b/day10/src/com/inmind/duotai_member09/Demo09.java
@@ -28,6 +28,10 @@ Person p = new Student();//这里才使用了多态
 
 一定要注意：编译看左边，运行看右边。
 多态中：代码的书写时，父类中没有的变量和方法是不能写的，因为编译看左边，编译器会直接报错
+
+多态的核心好处：“以不变，应万变”---通过抽象定义统一接口，应对具体实现的变化。它让代码简洁，灵活，更
+容易扩展。
+
  */
 public class Demo09 {
     public static void main(String[] args) {
diff --git a/day10/src/com/inmind/object_cast10/Animal.java b/day10/src/com/inmind/object_cast10/Animal.java
new file mode 100644
index 0000000..86cadde
--- /dev/null
+++ b/day10/src/com/inmind/object_cast10/Animal.java
@@ -0,0 +1,5 @@
+package com.inmind.object_cast10;
+
+public abstract class Animal {
+    public abstract void eat();
+}
diff --git a/day10/src/com/inmind/object_cast10/Cat.java b/day10/src/com/inmind/object_cast10/Cat.java
new file mode 100644
index 0000000..8898a14
--- /dev/null
+++ b/day10/src/com/inmind/object_cast10/Cat.java
@@ -0,0 +1,11 @@
+package com.inmind.object_cast10;
+
+public class Cat extends Animal{
+    @Override
+    public void eat() {
+        System.out.println("猫吃鱼");
+    }
+    public void catchMouse(){
+        System.out.println("猫抓老鼠");
+    }
+}
diff --git a/day10/src/com/inmind/object_cast10/Demo10.java b/day10/src/com/inmind/object_cast10/Demo10.java
new file mode 100644
index 0000000..17528d3
--- /dev/null
+++ b/day10/src/com/inmind/object_cast10/Demo10.java
@@ -0,0 +1,21 @@
+package com.inmind.object_cast10;
+/*
+对象的向上转型和向下转型：就是引用数据类型的类型转换
+
+注意：多态的向下转型，一定要是对应的类型才能转换，否则就报ClassCastException（类型转换异常）
+ */
+public class Demo10 {
+    public static void main(String[] args) {
+        //多态，来一只猫
+        //父类引用指向子类对象（多态）
+        Animal animal = new Cat();//向上转型
+        animal.eat();//编译时看左边，运行时看右边
+        //我就要这个动物，抓老鼠（把它转成猫再抓老鼠）
+        Cat cat = (Cat) animal;//向下转型
+        cat.catchMouse();
+
+        //我就要这个动物，看门（把它转成狗再看门）
+        Dog dog = (Dog) animal;//报错，此时animal引用的是Cat对象，无法转成Dog对象，会出现java.lang.ClassCastException
+        dog.lookHome();
+    }
+}
diff --git a/day10/src/com/inmind/object_cast10/Dog.java b/day10/src/com/inmind/object_cast10/Dog.java
new file mode 100644
index 0000000..7373122
--- /dev/null
+++ b/day10/src/com/inmind/object_cast10/Dog.java
@@ -0,0 +1,12 @@
+package com.inmind.object_cast10;
+
+public class Dog extends Animal{
+    @Override
+    public void eat() {
+        System.out.println("狗吃骨头");
+    }
+
+    public void lookHome(){
+        System.out.println("狗看家");
+    }
+}