From 43482ae2a4e515f41e4465e135aacf6a1fc9bd3c Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Tue, 21 Jul 2026 14:46:38 +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/Demo10.java | 39 ++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 day07/src/com/inmind/arraylist03/Demo10.java

diff --git a/day07/src/com/inmind/arraylist03/Demo10.java b/day07/src/com/inmind/arraylist03/Demo10.java
new file mode 100644
index 0000000..fed1168
--- /dev/null
+++ b/day07/src/com/inmind/arraylist03/Demo10.java
@@ -0,0 +1,39 @@
+package com.inmind.arraylist03;
+
+import java.util.ArrayList;
+
+/*
+基本类型	基本类型包装类
+byte	Byte
+short	Short
+int	    Integer
+long	Long
+float	Float
+double	Double
+char	Character
+boolean	Boolean
+
+常用类-ArrayList-基本类型的存储方式_转换为包装类
+自动装箱---int型的值，装箱成了引用数据类型Integer
+自动拆箱---Integer类型对象，自动拆箱为基本数据类型int
+
+基本数据类型4类8种，都有对应的包装类型，特殊记忆int：Integer  char：Character
+ */
+public class Demo10 {
+    public static void main(String[] args) {
+        //定义一个存放int型数据的集合
+        //ArrayList<int> list1 = new ArrayList<int>(); 错误
+        ArrayList<Integer> list1 = new ArrayList<Integer>();
+        list1.add(1);//自动装箱：int型 1  ---->Integer 类型的对象
+        list1.add(2);
+        list1.add(3);
+        System.out.println(list1);
+
+        //获取第二个值
+        Integer i = list1.get(1);
+        System.out.println(i);//此时i是引用数据类型，保存的是地址，但是底层源码修改了toString的效果
+        //包装类在数学运算时就会自动拆箱
+        int sum = i +10;//自动拆箱：i是Integer对象，自动拆箱为int型的2的整数
+        System.out.println(sum);//12
+    }
+}