From ed92b5ca56fff624488887e7ce42f67bb758dfc6 Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Tue, 20 Jan 2026 10:20:58 +0800
Subject: [PATCH] =?UTF-8?q?day07-=E5=B8=B8=E7=94=A8=E7=B1=BB-ArrayList-?=
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---
 day07/src/com/inmind/arraylist03/Demo09.java | 35 ++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 day07/src/com/inmind/arraylist03/Demo09.java

diff --git a/day07/src/com/inmind/arraylist03/Demo09.java b/day07/src/com/inmind/arraylist03/Demo09.java
new file mode 100644
index 0000000..a52b740
--- /dev/null
+++ b/day07/src/com/inmind/arraylist03/Demo09.java
@@ -0,0 +1,35 @@
+package com.inmind.arraylist03;
+/*
+ArrayList_基本类型的存储方式_转换为包装类
+
+自动装箱：int 型的值 -----装箱成Integer类型的对象
+自动拆箱：Integer类型的对象-----拆箱为int型的值
+4类8种的基本数据类型不能存放到集合中，因为集合只能存放引用数据类型
+
+在java中使用包装类，来对基本数据类型进行包装，包装成引用数据类型
+
+主要记忆int和char的包装类
+ */
+
+import java.util.ArrayList;
+
+public class Demo09 {
+    public static void main(String[] args) {
+        ArrayList<Integer> lists = new ArrayList<>();
+        //以下代码的含义：lists.add(new Integer(1));
+        lists.add(1);//自动装箱：内容为1的Integer对象
+        lists.add(2);
+        lists.add(3);
+        System.out.println(lists);
+
+        Integer i = lists.get(1);
+        int sum = i+10;//自动拆箱：i是Integer对象，拆箱为整型int 值，再参与运算
+        System.out.println(sum);//12
+        //创建一个保存字符的集合
+        ArrayList<Character> list2 = new ArrayList<>();
+        list2.add('a');
+        list2.add('b');
+        list2.add('c');
+        System.out.println(list2);
+    }
+}