From a791691c33f11463d7f8fafd347f5ef733617f96 Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Mon, 3 Aug 2026 10:59:59 +0800
Subject: [PATCH] =?UTF-8?q?s-day04-=E9=9B=86=E5=90=88=E7=9A=84=E5=B5=8C?=
 =?UTF-8?q?=E5=A5=97?=
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

---
 s-day04/src/com/inmind/map01/MapDemo07.java | 29 +++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 s-day04/src/com/inmind/map01/MapDemo07.java

diff --git a/s-day04/src/com/inmind/map01/MapDemo07.java b/s-day04/src/com/inmind/map01/MapDemo07.java
new file mode 100644
index 0000000..6890c08
--- /dev/null
+++ b/s-day04/src/com/inmind/map01/MapDemo07.java
@@ -0,0 +1,29 @@
+package com.inmind.map01;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+
+/*
+集合的嵌套
+
+使用集合的嵌套，显示哪个省份有哪些城市
+    省份作为Key String
+    城市作为值（有很多数据，容器集合）
+ */
+public class MapDemo07 {
+    public static void main(String[] args) {
+        //使用Map实现哪些省份有什么城市
+        //江苏省：南京市、无锡市、苏州市、南通市、常州市
+        //先准备城市
+        ArrayList<String> cityList1 = new ArrayList<>();
+        Collections.addAll(cityList1, "南京市", "无锡市", "苏州市", "南通市", "常州市");
+        ArrayList<String> cityList2 = new ArrayList<>();
+        Collections.addAll(cityList2, "杭州市", "宁波市", "温州市", "绍兴市");
+        //创建一个双列集合保存哪些省份有什么城市
+        HashMap<String, ArrayList<String>> maps = new HashMap<>();
+        maps.put("江苏省", cityList1);
+        maps.put("浙江省", cityList2);
+        System.out.println(maps);
+    }
+}