From 97843e6d313441d6a577f85dbf1a0f8babdb89e2 Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Thu, 15 Oct 2026 11:15:05 +0800
Subject: [PATCH] =?UTF-8?q?s-day04--Map=E9=9B=86=E5=90=88=E7=9A=84?=
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---
 s-day04/src/com/inmind/map01/MapDemo02.java | 40 +++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 s-day04/src/com/inmind/map01/MapDemo02.java

diff --git a/s-day04/src/com/inmind/map01/MapDemo02.java b/s-day04/src/com/inmind/map01/MapDemo02.java
new file mode 100644
index 0000000..f4fedce
--- /dev/null
+++ b/s-day04/src/com/inmind/map01/MapDemo02.java
@@ -0,0 +1,40 @@
+package com.inmind.map01;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+
+/*
+3.Map集合的第一种遍历方式(键找值)
+Map也是没有索引，也没有迭代器功能，所以不能通过普通for循环，也不能通过迭代器和foreach遍历，只能间接遍历
+
+- public Set<K> keySet(): 获取Map集合中所有的键，存储到Set集合中。
+ */
+public class MapDemo02 {
+    public static void main(String[] args) {
+        //创建一个键和值都是String的双列集合
+        Map<String, String> map = new HashMap<>();
+        map.put("刘备", "孙尚香");
+        map.put("吕布", "貂蝉");
+        map.put("张飞", "夏侯驰");
+        System.out.println(map);
+        //先获取双列集合中所有的键
+        Set<String> keys = map.keySet();
+        System.out.println(keys);
+
+        //set集合的增强for遍历
+        for (String key : keys) {
+            String value = map.get(key);
+            System.out.println(key+":"+value);
+        }
+        System.out.println("------------------------");
+        //set集合的迭代器遍历
+        Iterator<String> iterator = keys.iterator();
+        while (iterator.hasNext()) {
+            String key = iterator.next();
+            String value = map.get(key);
+            System.out.println(key+":"+value);
+        }
+    }
+}