{"id":10020375,"date":"2024-11-05T09:32:08","date_gmt":"2024-11-05T01:32:08","guid":{"rendered":"https:\/\/itmax.cn\/?p=10020375"},"modified":"2024-11-05T09:32:08","modified_gmt":"2024-11-05T01:32:08","slug":"%e5%85%ac%e5%8f%b8%e6%9d%a5%e4%ba%86%e4%b8%aa%e6%96%b0%e5%90%8c%e4%ba%8b%ef%bc%8c%e6%8a%8a%e4%bb%a3%e7%a0%81%e8%80%97%e6%97%b6%e4%bb%8e-26856ms-%e4%bc%98%e5%8c%96%e5%88%b0%e4%ba%86-748ms%ef%bc%8c","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10020375","title":{"rendered":"\u516c\u53f8\u6765\u4e86\u4e2a\u65b0\u540c\u4e8b\uff0c\u628a\u4ee3\u7801\u8017\u65f6\u4ece 26856ms \u4f18\u5316\u5230\u4e86 748ms\uff0c\u4e00\u987f\u64cd\u4f5c\u731b\u5982\u864e\uff01"},"content":{"rendered":"

\u5728\u4e24\u4efd\u8868\u91cc\u627e\u76f8\u540cid\u7684\u6570\u636e\uff0c\u5f88\u591a\u540c\u5b66\u4f1a\u5199\u4e24\u4e2afor\u5faa\u73af\u5d4c\u5957\u3002\u8fd9\u4e2a\u5199\u6cd5\u6548\u7387\u6bd4\u8f83\u4f4e\uff0c\u4eca\u5929\u6765\u770b\u4e00\u4e2a\u63d0\u9ad8\u901f\u5ea6\u7684\u4f18\u5316\u6848\u4f8b\u3002<\/p>\n

\u672c\u7bc7\u5206\u6790\u7684\u6280\u5de7\u70b9\u5176\u5b9e\u662f\u6bd4\u8f83\u5e38\u89c1\u7684\uff0c\u4f46\u662f\u6700\u8fd1\u7684\u51e0\u6b21\u7684\u4ee3\u7801\u8bc4\u5ba1\u8fd8\u662f\u53d1\u73b0\u6709\u4e0d\u5c11\u5144\u5f1f\u6ca1\u6ce8\u610f\u5230\u3002\u6240\u4ee5\u8fd8\u662f\u60f3\u62ff\u51fa\u6765\u8bf4\u4e0b\u3002<\/p>\n

\u662f\u4e2a\u4ec0\u4e48\u573a\u666f\u5462\uff1f\u5c31\u662f for\u5faa\u73af \u91cc\u9762\u8fd8\u6709 for\u5faa\u73af\uff0c \u7136\u540e\u505a\u4e00\u4e9b\u6570\u636e\u5339\u914d\u3001\u5904\u7406 \u8fd9\u79cd\u573a\u666f\u3002<\/p>\n

\u6211\u4eec\u7ed3\u5408\u5b9e\u4f8b\u4ee3\u7801\u6765\u770b\u770b\u3002\u573a\u666f\u793a\u4f8b\uff1a<\/p>\n

\u6bd4\u5982\u6211\u4eec\u73b0\u5728\u62ff\u5230\u4e24\u4e2alist \u6570\u636e \uff0c\u4e00\u4e2a\u662f User List \u96c6\u5408 \uff1b\u53e6\u4e00\u4e2a\u662f UserMemo List\u96c6\u5408\uff1b<\/p>\n

\u6211\u4eec\u9700\u8981\u904d\u5386 User List \uff0c\u7136\u540e\u6839\u636e userId \u4ece UserMemo List \u91cc\u9762\u53d6\u51fa \u5bf9\u5e94\u8fd9\u4e2auserId \u7684 content \u503c\uff0c\u505a\u6570\u636e\u5904\u7406\u3002<\/p>\n

\u4ee3\u7801 User.java \uff1a<\/p>\n

@Data\npublic class User {\n    private Long userId;\n    private String name;\n}<\/code><\/pre>\n
\u4ee3\u7801 UserMemo.java \uff1a<\/p>\n
@Data\npublic class UserMemo {\n    private Long userId;\n    private String content;\n}<\/code><\/pre>\n
\u6a21\u62df\u6570\u636e\u96c6\u5408 \uff1a5W \u6761 user \u6570\u636e \uff0c 3W\u6761 userMemo\u6570\u636e<\/p>\n
public static List<User> getUserTestList() {\n        List<User> users = new ArrayList<>();\n        for (int i = 1; i <= 50000; i++) {\n            User user = new User();\n            user.setName(UUID.randomUUID().toString());\n            user.setUserId((long) i);\n            users.add(user);\n        }\n        return users;\n    }\n\n    public static List<UserMemo> getUserMemoTestList() {\n        List<UserMemo> userMemos = new ArrayList<>();\n        for (int i = 30000; i >= 1; i--) {\n            UserMemo userMemo = new UserMemo();\n            userMemo.setContent(UUID.randomUUID().toString());\n            userMemo.setUserId((long) i);\n            userMemos.add(userMemo);\n        }\n        return userMemos;\n    }<\/code><\/pre>\n
\u5148\u770b\u5e73\u65f6\u5927\u5bb6\u4e0d\u6ce8\u610f\u7684\u65f6\u5019\u53ef\u80fd\u4f1a\u8fd9\u6837\u53bb\u5199\u4ee3\u7801\u5904\u7406 \uff1a<\/p>\n
\"\"<\/p>\n
\u5176\u5b9e\u6570\u636e\u91cf\u5c0f\u7684\u8bdd\uff0c\u5176\u5b9e\u6ca1\u591a\u5927\u6027\u80fd\u5dee\u522b\uff0c\u4e0d\u8fc7\u6211\u4eec\u8fd8\u662f\u9700\u8981\u77e5\u9053\u4e00\u4e9b\u6280\u5de7\u70b9\u3002\u6211\u4eec\u6765\u770b\u770b \u8fd9\u65f6\u5019\u7684\u4e00\u4e2a\u8017\u65f6\u60c5\u51b5 \u3002<\/p>\n
\u76f8\u5f53\u4e8e\u8fed\u4ee3\u4e86 5W * 3W \u6b21 \uff0c\u53ef\u4ee5\u770b\u5230\u7528\u65f6 \u662f 26857\u6beb\u79d2 \uff1a<\/p>\n
\"\"<\/p>\n
\u5176\u5b9e\u5230\u8fd9\uff0c\u63d2\u5165\u4e2a\u9898\u5916\u70b9\uff0c\u5982\u679c\u8bf4\u6bcf\u4e2auserId \u5728 UserMemo List \u91cc\u9762 \u90fd\u662f\u53ea\u6709\u4e00\u6761\u6570\u636e\u7684\u573a\u666f\u3002<\/p>\n
for (User user : userTestList) {\n    Long userId = user.getUserId();\n    for (UserMemo userMemo : userMemoTestList) {\n        if (userId.equals(userMemo.getUserId())) {\n            String content = userMemo.getContent();\n            System.out.println("\u6a21\u62df\u6570\u636econtent \u4e1a\u52a1\u5904\u7406......"+content);\n        }\n    }\n}<\/code><\/pre>\n
\u5355\u4ece\u8fd9\u6bb5\u4ee3\u7801\u6709\u6ca1\u6709\u95ee\u9898 \uff0c\u6709\u6ca1\u6709\u4f18\u5316\u70b9\u3002\u663e\u7136\u662f\u6709\u7684\uff0c \u56e0\u4e3a\u5f53\u6211\u4eec\u4ece\u5185\u5faa\u73afUserMemo List\u91cc\u9762\u627e\u5230\u5339\u914d\u6570\u636e\u7684\u65f6\u5019\uff0c \u6ca1\u6709\u505a\u5176\u4ed6\u64cd\u4f5c\u4e86\u3002<\/p>\n
\u8fd9\u6837\u5185for\u5faa\u73af\u4f1a\u7ee7\u7eed\u4e0b\uff0c\u76f4\u5230\u8dd1\u5b8c\u518d\u8fdb\u884c\u4e0b\u4e00\u8f6e\u6574\u4f53\u5faa\u73af\u3002\u6240\u4ee5\uff0c\u4ec5\u9488\u5bf9\u8fd9\u79cd\u60c5\u5f62\uff0c1\u5bf91\u7684\u6216\u8005\u8bf4\u6211\u4eec\u53ea\u9700\u8981\u627e\u5230\u4e00\u4e2a\u5339\u914d\u9879\uff0c\u5904\u7406\u5b8c\u540e\u6211\u4eec \u5e94\u8be5\u4f7f\u7528 break \u3002<\/p>\n
\u6211\u4eec\u6765\u770b\u770b\u52a0\u4e0a break \u7684\u4e00\u4e2a\u8017\u65f6\u60c5\u51b5 \uff1a<\/p>\n
\"\"<\/p>\n
\u8017\u65f6\u60c5\u51b5\uff1a\u53ef\u4ee5\u770b\u5230 \u4ece 2W \u591a\u6beb\u79d2 \u53d8\u6210\u4e86 1W \u591a\u6beb\u79d2\uff0c \u8fd9\u4e2abreak \u52a0\u7684\u5f88OK\u3002<\/p>\n
\"\"<\/p>\n
\u56de\u5230\u6211\u4eec\u521a\u624d, \u5e73\u65f6\u9700\u8981for \u5faa\u73af\u91cc\u9762\u518d for \u5faa\u73af \u8fd9\u79cd\u65b9\u5f0f\uff0c\u53ef\u4ee5\u770b\u5230\u8017\u65f6\u662f 2\u4e076\u5343\u591a\u6beb\u79d2\u3002<\/p>\n
\u90a3\u5982\u679c\u573a\u666f\u66f4\u590d\u6742\u4e00\u5b9a\uff0c \u662ffor \u5faa\u73af\u91cc\u9762 for\u5faa\u73af \u591a\u4e2a\u6216\u8005\uff0c for\u5faa\u73af\u91cc\u9762\u8fd8\u6709\u4e00\u5c42for \u5faa\u73af \uff0c\u90a3\u8fd9\u6837\u4ee3\u7801\u8017\u65f6\u771f\u7684\u975e\u5e38\u6050\u6016\u3002<\/p>\n
\u90a3\u4e48\u63a5\u4e0b\u6765\u8fd9\u4e2a\u6280\u5de7\u70b9\u662f\u4f7f\u7528map \u53bb\u4f18\u5316 \uff1a<\/p>\n
\"\"<\/p>\n
\u4ee3\u7801\uff1a<\/p>\n
    public static void main(String[] args) {\n        List<User> userTestList = getUserTestList();\n        List<UserMemo> userMemoTestList = getUserMemoTestList();\n\n        StopWatch stopWatch = new StopWatch();\n        stopWatch.start();\n        \/\/\u4f7f\u7528stream() \u8bb0\u5f97\u4e00\u5b9a\u8981\u5224\u7a7a \u8fd9\u91cc\u6ca1\u5217\u51fa\u6765\uff0c\u5927\u5bb6\u81ea\u5df1\u6ce8\u610f\n        Map<Long, String> contentMap =\n                userMemoTestList.stream().collect(Collectors.toMap(UserMemo::getUserId, UserMemo::getContent));\n\n        for (User user : userTestList) {\n            Long userId = user.getUserId();\n            String content = contentMap.get(userId);\n\n            if (StringUtils.hasLength(content)) {\n                System.out.println("\u6a21\u62df\u6570\u636econtent \u4e1a\u52a1\u5904\u7406......" + content);\n            }\n\n        }\n\n        stopWatch.stop();\n        System.out.println("\u6700\u7ec8\u8017\u65f6" + stopWatch.getTotalTimeMillis());\n\n    }<\/code><\/pre>\n
\u770b\u770b\u8017\u65f6:<\/p>\n
\"\"<\/p>\n
\u4e3a\u4ec0\u4e48\u6548\u679c\u8fd9\u4e48\u663e\u8457\uff1f<\/p>\n
\u8fd9\u5176\u5b9e\u5c31\u662f\u65f6\u95f4\u590d\u6742\u5ea6\uff0cfor\u5faa\u73af\u5d4c\u5957for\u5faa\u73af\uff0c\u5c31\u597d\u6bd4 \u5faa\u73af\u6bcf\u4e00\u4e2a user \uff0c\u62ff\u51fa userId \u9700\u8981\u5728\u91cc\u9762\u7684\u5faa\u73af\u4ece userMemo list\u96c6\u5408\u91cc\u9762 \u6309\u987a\u5e8f\u53bb\u5f00\u76f2\u76d2\u5339\u914d,\u62ff\u51fa\u7b2c\u4e00\u4e2a\uff0c\u770b\u770buserId \uff0c\u62ff\u51fa\u7b2c\u4e8c\u4e2a\uff0c\u770b\u770buserId \uff0c\u4e00\u76f4\u627e\u5339\u914d\u7684\u3002<\/p>\n
\u800c\u6211\u4eec\u63d0\u524d\u5bf9 userMemo list\u96c6\u5408 \u505a\u4e00\u6b21 \u904d\u5386\uff0c\u8f6c\u5b58\u50a8\u5728map\u91cc\u9762 \u3002<\/p>\n
map\u7684\u53d6\u503c\u6548\u7387 \u5728\u591a\u6570\u7684\u60c5\u51b5\u4e0b\u662f\u80fd\u7ef4\u6301\u63a5\u8fd1 O\uff081\uff09 \u7684 \uff0c \u6bd5\u7adf\u6570\u636e\u7ed3\u6784\u6446\u7740\uff0c\u6570\u7ec4\u52a0\u94fe\u8868\u3002<\/p>\n
\u76f8\u5f53\u4e8e\u62ff\u5230userId  \u60f3\u53bb\u5f00\u76f2\u76d2\u7684\u65f6\u5019\uff0c \u6839\u636euserId \u8fd9\u4e2akey  hash\u5b8c\u80fd\u76f4\u63a5\u627e\u5230\u6570\u7ec4\u91cc\u9762\u7684\u7d22\u5f15\u6807\u8bb0\u4f4d\uff0c \u5982\u679c\u5e95\u4e0b\u6ca1\u94fe\u8868\uff08\u6709\u7684\u8bddO(logN)\uff09\uff0c\u76f4\u63a5\u53d6\u51fa\u6765\u5c31\u5b8c\u4e8b\u4e86\u3002<\/p>\n
\"\"<\/p>\n
\u6309\u7167\u76ee\u524d\u4ee5JDK8 \u7684hash\u7b97\u6cd5\uff0c\u8d77hash\u51b2\u7a81\u7684\u60c5\u51b5\u662f\u975e\u5e38\u975e\u5e38\u5c11\u89c1\u4e86\u3002<\/p>\n
\u6700\u6076\u52a3\u7684\u60c5\u51b5\uff0c\u53ea\u6709\u5f53 \u5168\u90e8key \u90fd\u51b2\u7a81\uff0c \u5168\u90fd\u5206\u914d\u5230\u4e00\u4e2a\u6876\u91cc\u9762\u53bb\u90fd\u5360\u7528\u4e00\u4e2a\u4f4d\u7f6e \uff0c\u8fd9\u65f6\u5019\u5c31\u662fO\uff08n\uff09\uff0c\u8fd9\u79cd\u60c5\u666f\u4e0d\u9700\u8981\u53bb\u8003\u8651\u3002<\/p>\n
\u539f\u6587\uff1ahttps:\/\/blog.csdn.net\/qq_35387940\/article\/details\/129518893<\/a><\/p>\n
\u66f4\u591a\u6587\u7ae0\u63a8\u8350\uff1a<\/strong><\/p>\n
1.Spring Boot 3.x \u6559\u7a0b\uff0c\u592a\u5168\u4e86\uff01<\/a><\/p>\n
2.2,000+ \u9053 Java\u9762\u8bd5\u9898\u53ca\u7b54\u6848\u6574\u7406(2024\u6700\u65b0\u7248)<\/a><\/p>\n
3.\u514d\u8d39\u83b7\u53d6 IDEA \u6fc0\u6d3b\u7801\u7684 7 \u79cd\u65b9\u5f0f\uff082024\u6700\u65b0\u7248\uff09<\/a><\/p>\n
\u89c9\u5f97\u4e0d\u9519\uff0c\u522b\u5fd8\u4e86\u968f\u624b\u70b9\u8d5e+\u8f6c\u53d1\u54e6\uff01<\/p>\n
https:\/\/segmentfault.com\/a\/1190000045448059<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
\u5728\u4e24\u4efd\u8868\u91cc\u627e\u76f8\u540cid\u7684\u6570\u636e\uff0c\u5f88\u591a\u540c\u5b66\u4f1a\u5199\u4e24\u4e2afor\u5faa\u73af\u5d4c\u5957\u3002\u8fd9\u4e2a\u5199\u6cd5\u6548\u7387\u6bd4\u8f83\u4f4e\uff0c\u4eca\u5929\u6765\u770b\u4e00\u4e2a\u63d0\u9ad8\u901f\u5ea6\u7684\u4f18\u5316\u6848\u4f8b […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-10020375","post","type-post","status-publish","format-standard","hentry","category-share"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10020375","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10020375"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10020375\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10020375"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10020375"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10020375"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}