From 63ee31eacf535d0f800942963dc91bef88ea2473 Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Thu, 30 Jul 2026 14:47:41 +0800
Subject: [PATCH] =?UTF-8?q?s-day01-=E5=8C=85=E8=A3=85=E7=B1=BB=E8=87=AA?=
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---
 s-day01/src/com/inmind/wrap08/Demo18.java | 63 +++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 s-day01/src/com/inmind/wrap08/Demo18.java

diff --git a/s-day01/src/com/inmind/wrap08/Demo18.java b/s-day01/src/com/inmind/wrap08/Demo18.java
new file mode 100644
index 0000000..275163c
--- /dev/null
+++ b/s-day01/src/com/inmind/wrap08/Demo18.java
@@ -0,0 +1,63 @@
+package com.inmind.wrap08;
+/*
+    java中 4类8种基本数据类型，有对应引用数据类型（包装类对应）【为了保存到容器ArrayList中】
+    byte                Byte
+    short               Short
+    int                 Integer
+    long                Long
+    float               Float
+    double              Double
+    char                Character
+    boolean             Boolean
+
+    jdk1.5自动拆装箱子
+    拆箱：
+        包装类------基本类型
+    装箱
+        基本类型------包装类
+  -----------------------------------------------------
+  字符串与基本类型的转换
+    在实际开发中，我们接收用户输入的字符串，大部分是String，但是我们java进行数据的计算也就是基本类型。
+
+    需求场景：
+    基本类型-----String
+    + “”||stringbuilder的append方法
+    String -----基本类型
+    包装类名.parseXXX(字符串)
+ */
+public class Demo18 {
+    public static void main(String[] args) {
+        int i = 10;
+        Integer i1 = 20;//自动装箱
+        System.out.println(i1 + 20);//自动拆箱
+        System.out.println("------------------------------------");
+        //基本类型转字符串
+        int j = 10;
+        String s1 = j + "";
+        String s2 = new StringBuilder().append(j).append(10.0).append(true).toString();
+        System.out.println(s1);
+        System.out.println(s2);
+        //字符串转基本类型【包装类名.parseXXX(字符串)】
+        String s3 = "2.0";
+        double d = Double.parseDouble(s3);
+        System.out.println(d);
+
+        String s4 = "3.0f";
+        float f = Float.parseFloat(s4);
+        System.out.println(f);
+
+        String s5 = "true";
+        boolean b = Boolean.parseBoolean(s5);
+        System.out.println(b);
+
+        //字符串转char【特殊情况】
+        String s6 = "abc";
+        char[] chars = s6.toCharArray();
+        char c = s6.charAt(0);
+
+        String s7 = "100";//【最常见】
+        int i2 = Integer.parseInt(s7);
+        System.out.println(i2);
+
+    }
+}