{"id":2188,"date":"2025-08-09T15:31:51","date_gmt":"2025-08-09T07:31:51","guid":{"rendered":"https:\/\/note.ui11.cc\/?p=2188"},"modified":"2025-08-10T09:20:34","modified_gmt":"2025-08-10T01:20:34","slug":"%e9%9b%86%e5%90%88%e5%ad%a6%e4%b9%a02025-8-9","status":"publish","type":"post","link":"https:\/\/note.ui11.cc\/index.php\/2025\/08\/09\/%e9%9b%86%e5%90%88%e5%ad%a6%e4%b9%a02025-8-9\/","title":{"rendered":"\u4e0d\u53ef\u53d8\u96c6\u5408\u5b66\u4e602025\/8\/9"},"content":{"rendered":"\n

\u521b\u5efa\u4e0d\u53ef\u53d8\u96c6\u5408\uff1alist.of()<\/strong><\/p>\n\n\n\n

\"\"<\/div><\/figure>\n\n\n\n
package cn.zhage.collectionstudy.map;\n\nimport org.junit.jupiter.api.Test;\nimport org.springframework.boot.test.context.SpringBootTest;\n\nimport java.util.Iterator;\nimport java.util.List;\n\n@SpringBootTest\npublic class mapDemo {\n    \/\/\u521b\u5efa\u4e0d\u53ef\u53d8\u96c6\u5408\n\n    @Test\n    public void test1()\n    {\n\n\/\/\u7b80\u5355\u7406\u89e3\uff1a\u4e0d\u60f3\u8ba9\u522b\u4eba\u4fee\u6539\u96c6\u5408\u4e2d\u5185\u5bb9\n\/\/\u6bd4\u5982\u5728\u67d0\u4e9b\u573a\u5408\u4e00\u4e9b\u6570\u636e\u4e0d\u5141\u8bb8\u4fee\u6539\uff0c\u4ee3\u7801\u5c42\u9762\u4e0d\u53ef\u4fee\u6539\n\n        List<Integer> list = List.of(1, 2, 3);\n        List<String> name = List.of(\"\u4ed8\u6c38\u95ef\");\/\/\u521b\u5efa\u4e0d\u53ef\u53d8\u96c6\u5408\n        \/\/\u4e00\u65e6\u521b\u5efa\u6210\u529f\uff0c\u4e0d\u53ef\u4fee\u6539\uff0c\u53ea\u80fd\u8fdb\u884c\u67e5\u8be2\n        System.out.println(list.get(0));\n        System.out.println(name);\n        Iterator<Integer> iterator = list.iterator();\n        \/\/\u8fed\u4ee3\u5668\n        while (iterator.hasNext())\n        {\n            System.out.println(iterator.next());\n        }\n        \/\/\u589e\u5f3afor\u5faa\u73af\n        for (Integer i : list) {\n            System.out.println(i);\n        }\n           \/\/\u666e\u901afor\u5faa\u73af\n        for (int i = 0; i < list.size(); i++) {\n            System.out.println(list.get(i));\n        }\n\/\/\u5982\u679c\u6211\u4eec\u8981\u4fee\u6539\u5143\u7d20\uff0c\u8fd9\u662f\u4e0d\u5141\u8bb8\u7684\uff0c\u6bd4\u5982\u6211\u4eec\u5220\u9664\u96c6\u5408list\u4e2d\u7684\u5143\u7d20\n        list.remove(0);\n\n\n    }\n\n\n\n\n\n}<\/code><\/pre>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
\u4fee\u6539\u64cd\u4f5c\u4e5f\u662f\u4e0d\u5141\u8bb8\u7684<\/p>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
\u540c\u6837\u7684\u8fd8\u6709set\u96c6\u5408\uff0c\u548clist\u4e00\u6837\uff0cset\u96c6\u5408\u6ca1\u7d22\u5f15\uff0c\u8981\u60f3\u67e5\u8be2\u53ea\u80fd\u904d\u5386<\/strong><\/p>\n\n\n\n
Map.of()\u4e5f\u662f\u4e0d\u53ef\u53d8\u96c6\u5408<\/p>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
java\u9ed8\u8ba4\u4f1a\u8ba4\u4e3a\u524d\u4e24\u4e2a\u5143\u7d20\u662f\u4e00\u4e2a\u952e\u503c\u5bf9\uff0c\u4ee5\u6b64\u7c7b\u63a8<\/strong><\/p>\n\n\n\n
map.keySet\uff08\uff09\u4f1a\u5f97\u5230\u96c6\u5408\u4e2d\u6240\u6709\u7684\u952e<\/strong><\/p>\n\n\n\n
import java.util.HashMap;\nimport java.util.Map;\nimport java.util.Set;\n\npublic class Main {\n    public static void main(String[] args) {\n        Map<String, Integer> map = new HashMap<>();\n        map.put(\"a\", 1);\n        map.put(\"b\", 2);\n        map.put(\"c\", 3);\n        \n        Set<String> keys = map.keySet();\n        System.out.println(keys); \/\/ \u8f93\u51fa [a, b, c]\n    }\n}<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\uff1a\u8fd9\u91cc\u662f\u5f97\u5230\u7684\u6bcf\u4e00\u4e2a\u952e<\/p>\n\n\n\n
2. \u904d\u5386\u6240\u6709\u503c\uff08values()<\/code>\uff09<\/h3>\n\n\n\n
\u5982\u679c\u53ea\u9700\u8981\u503c\uff0c\u53ef\u901a\u8fc7 values()<\/code> \u76f4\u63a5\u83b7\u53d6\u503c\u7684\u96c6\u5408\uff1a<\/p>\n\n\n\n
\/\/ \u904d\u5386\u503c\uff08\u4e0d\u5173\u5fc3\u952e\uff09\nfor (Integer value : map.values()) {\n    System.out.println(\"\u503c\uff1a\" + value);\n}<\/code><\/pre>\n\n\n\n
3. \u904d\u5386\u952e\u503c\u5bf9\uff08entrySet()<\/code>\uff0c\u63a8\u8350\uff09<\/h3>\n\n\n\n
\u901a\u8fc7 entrySet()<\/code> \u83b7\u53d6\u952e\u503c\u5bf9\uff08Map.Entry<\/code>\uff09\u7684\u96c6\u5408\uff0c\u540c\u65f6\u83b7\u53d6\u952e\u548c\u503c\uff0c\u6548\u7387\u6bd4\u5148\u904d\u5386\u952e\u518d\u67e5\u503c\u66f4\u9ad8\uff1a<\/p>\n\n\n\n
\/\/ \u904d\u5386\u952e\u503c\u5bf9\uff08\u63a8\u8350\uff0c\u6548\u7387\u9ad8\uff09\nfor (Map.Entry<String, Integer> entry : map.entrySet()) {\n    String key = entry.getKey();\n    Integer value = entry.getValue();\n    System.out.println(\"\u952e\uff1a\" + key + \"\uff0c\u503c\uff1a\" + value);\n}<\/code><\/pre>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
java9\u7279\u6027\uff1a<\/p>\n\n\n\n
\u573a\u666f 2\uff1a\u5148\u5b58\u6570\u636e\u5230\u53ef\u53d8 Map<\/code>\uff0c\u518d\u8f6c\u4e0d\u53ef\u53d8\uff08\u5982\u679c\u9700\u8981\uff09<\/h3>\n\n\n\n
\u5982\u679c\u9700\u8981\u5148\u52a8\u6001\u5b58\u6570\u636e\uff0c\u6700\u540e\u8f6c\u4e0d\u53ef\u53d8<\/strong>\uff0c\u53ef\u4ee5\u8fd9\u6837\uff1a<\/p>\n\n\n\n
\/\/ 1. \u5148\u7528\u53ef\u53d8 Map \u5b58\u6570\u636e\uff08\u6bd4\u5982 HashMap\uff09\nMap<String, String> mutableMap = new HashMap<>();\nmutableMap.put(\"\u8d75\u516d\", \"\u5317\u4eac\");\nmutableMap.put(\"\u5b59\u4e03\", \"\u6df1\u5733\");\n\/\/ ... \u653e 10 \u4e2a\u4ee5\u4e0a\u6570\u636e\n\n\/\/ 2. \u8f6c\u6210\u4e0d\u53ef\u53d8 Map\uff08Java 9+ \u652f\u6301\uff09\nMap<String, String> immutableMap = Map.copyOf(mutableMap);\n\n\/\/ \u6ce8\u610f\uff1a\u4e0d\u53ef\u53d8 Map \u4e0d\u652f\u6301 put\uff0c\u4ee5\u4e0b\u4ee3\u7801\u4f1a\u62a5\u9519\uff01\n\/\/ immutableMap.put(\"\u65b0\u952e\", \"\u65b0\u503c\"); \/\/ \u629b UnsupportedOperationException<\/code><\/pre>\n\n\n\n
\u5728 Java \u4e2d\uff0cMap.copyOf(...)<\/code> \u65b9\u6cd5\u4f1a\u8fd4\u56de\u4e00\u4e2a\u4e0d\u53ef\u53d8\u7684 Map<\/code> \u96c6\u5408<\/strong>\u3002<\/p>\n\n\n\n
\u8be5\u65b9\u6cd5\u63a5\u6536\u4e00\u4e2a\u73b0\u6709\u7684 Map<\/code> \u4f5c\u4e3a\u53c2\u6570\uff0c\u8fd4\u56de\u4e00\u4e2a\u5305\u542b\u76f8\u540c\u952e\u503c\u5bf9\u7684\u65b0 Map<\/code>\uff0c\u4f46\u8fd9\u4e2a\u65b0 Map<\/code> \u5177\u6709\u4ee5\u4e0b\u7279\u6027\uff1a<\/p>\n\n\n\n
    \n
  • \u4e0d\u53ef\u4fee\u6539<\/strong>\uff1a\u4e0d\u652f\u6301\u00a0put<\/code>\u3001remove<\/code>\u00a0\u7b49\u4fee\u6539\u64cd\u4f5c\uff0c\u8c03\u7528\u8fd9\u4e9b\u65b9\u6cd5\u4f1a\u629b\u51fa\u00a0UnsupportedOperationException<\/code><\/li>\n\n\n\n
  • \u53ea\u8bfb\u6027<\/strong>\uff1a\u53ea\u80fd\u8fdb\u884c\u67e5\u8be2\u64cd\u4f5c\uff08\u5982\u00a0get<\/code>\u3001containsKey<\/code>\u00a0\u7b49\uff09<\/li>\n\n\n\n
  • \u503c\u4e0d\u53ef\u53d8<\/strong>\uff1a\u5982\u679c\u539f\u00a0Map<\/code>\u00a0\u4e2d\u7684\u503c\u662f\u53ef\u53d8\u5bf9\u8c61\uff0c\u867d\u7136\u53ef\u4ee5\u4fee\u6539\u5bf9\u8c61\u672c\u8eab\u7684\u72b6\u6001\uff0c\u4f46\u65e0\u6cd5\u66ff\u6362\u6574\u4e2a\u952e\u503c\u5bf9<\/li>\n<\/ul>\n\n\n\n
    import java.util.HashMap;\nimport java.util.Map;\n\npublic class Main {\n    public static void main(String[] args) {\n        \/\/ \u521b\u5efa\u4e00\u4e2a\u53ef\u53d8\u7684 HashMap\n        Map<String, Integer> mutableMap = new HashMap<>();\n        mutableMap.put(\"a\", 1);\n        mutableMap.put(\"b\", 2);\n        \n        \/\/ \u8f6c\u6362\u4e3a\u4e0d\u53ef\u53d8 Map\n        Map<String, Integer> immutableMap = Map.copyOf(mutableMap);\n        \n        \/\/ \u5c1d\u8bd5\u4fee\u6539\u4f1a\u629b\u51fa\u5f02\u5e38\n        try {\n            immutableMap.put(\"c\", 3); \/\/ \u4e0d\u652f\u6301\u6dfb\u52a0\u65b0\u5143\u7d20\n        } catch (UnsupportedOperationException e) {\n            System.out.println(\"\u65e0\u6cd5\u6dfb\u52a0\u5143\u7d20\uff1a\" + e.getMessage());\n        }\n        \n        try {\n            immutableMap.remove(\"a\"); \/\/ \u4e0d\u652f\u6301\u5220\u9664\u5143\u7d20\n        } catch (UnsupportedOperationException e) {\n            System.out.println(\"\u65e0\u6cd5\u5220\u9664\u5143\u7d20\uff1a\" + e.getMessage());\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
    <\/p>\n\n\n\n
    <\/p>\n","protected":false},"excerpt":{"rendered":"
    \u521b\u5efa\u4e0d\u53ef\u53d8\u96c6\u5408\uff1alist.of() \u4fee\u6539\u64cd\u4f5c\u4e5f\u662f\u4e0d\u5141\u8bb8\u7684 \u540c\u6837\u7684\u8fd8\u6709set\u96c6\u5408\uff0c\u548clist\u4e00\u6837\uff0cset\u96c6\u5408\u6ca1\u7d22 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,17],"tags":[],"class_list":["post-2188","post","type-post","status-publish","format-standard","hentry","category-javase","category-17"],"_links":{"self":[{"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/posts\/2188","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/comments?post=2188"}],"version-history":[{"count":2,"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/posts\/2188\/revisions"}],"predecessor-version":[{"id":2199,"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/posts\/2188\/revisions\/2199"}],"wp:attachment":[{"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/media?parent=2188"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/categories?post=2188"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/note.ui11.cc\/index.php\/wp-json\/wp\/v2\/tags?post=2188"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}