{"id":202836,"date":"2025-05-22T08:33:14","date_gmt":"2025-05-22T00:33:14","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202836\/"},"modified":"2025-05-22T08:33:14","modified_gmt":"2025-05-22T00:33:14","slug":"java%e5%87%bd%e6%95%b0%e4%b8%ad%e4%bc%98%e5%8c%96%e5%86%85%e5%ad%98%e4%bd%bf%e7%94%a8%e7%9a%84%e6%a8%a1%e5%bc%8f%e5%92%8c%e5%8f%8d%e6%a8%a1%e5%bc%8f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202836\/","title":{"rendered":"Java\u51fd\u6570\u4e2d\u4f18\u5316\u5185\u5b58\u4f7f\u7528\u7684\u6a21\u5f0f\u548c\u53cd\u6a21\u5f0f"},"content":{"rendered":"

<\/b> <\/p>\n

Java\u51fd\u6570\u4e2d\u4f18\u5316\u5185\u5b58\u4f7f\u7528\u7684\u6a21\u5f0f\u548c\u53cd\u6a21\u5f0f<\/h1>\n

\u6709\u5fd7\u8005\uff0c\u4e8b\u7adf\u6210\uff01\u5982\u679c\u4f60\u5728\u5b66\u4e60\u6587\u7ae0<\/span>\uff0c\u90a3\u4e48\u672c\u6587\u300aJava\u51fd\u6570\u4e2d\u4f18\u5316\u5185\u5b58\u4f7f\u7528\u7684\u6a21\u5f0f\u548c\u53cd\u6a21\u5f0f\u300b<\/span>\uff0c\u5c31\u5f88\u9002\u5408\u4f60\uff01\u6587\u7ae0\u8bb2\u89e3\u7684\u77e5\u8bc6\u70b9\u4e3b\u8981\u5305\u62ec<\/span>\uff0c\u82e5\u662f\u4f60\u5bf9\u672c\u6587\u611f\u5174\u8da3\uff0c\u6216\u8005\u662f\u60f3\u641e\u61c2\u5176\u4e2d\u67d0\u4e2a\u77e5\u8bc6\u70b9\uff0c\u5c31\u8bf7\u4f60\u7ee7\u7eed\u5f80\u4e0b\u770b\u5427~<\/span><\/p>\n

Java \u5185\u5b58\u4f18\u5316\u6a21\u5f0f\u5305\u62ec\uff1a1. \u7f13\u5b58\u7ed3\u679c\uff1b2. \u4f7f\u7528 StringBuilder\uff1b3. \u907f\u514d\u91cd\u590d\u5f15\u7528\u3002\u53cd\u6a21\u5f0f\u5305\u62ec\uff1a1. \u5185\u5b58\u6cc4\u6f0f\uff1b2. \u6808\u6ea2\u51fa\uff1b3. \u8fc7\u65e9\u4f18\u5316\u3002\u5b9e\u6218\u793a\u4f8b\uff1a\u6d41\u5904\u7406\u53ef\u7528\u4e8e\u4f18\u5316\u6570\u636e\u67e5\u8be2\uff0c\u901a\u8fc7\u9010\u884c\u5904\u7406\u6570\u636e\u8282\u7701\u5185\u5b58\u7a7a\u95f4\u3002<\/p>\n

<\/p>\n

Java \u51fd\u6570\u4e2d\u4f18\u5316\u5185\u5b58\u4f7f\u7528\u7684\u6a21\u5f0f\u548c\u53cd\u6a21\u5f0f<\/h2>\n

\u5185\u5b58\u4f18\u5316\u662f\u4efb\u4f55 Java \u7a0b\u5e8f\u5458\u90fd\u5e94\u8be5\u638c\u63e1\u7684\u91cd\u8981\u6280\u672f\u3002\u9075\u5faa\u6700\u4f73\u5b9e\u8df5\u53ef\u4ee5\u663e\u7740\u6539\u5584\u5e94\u7528\u7a0b\u5e8f\u6027\u80fd\uff0c\u907f\u514d\u5185\u5b58\u6cc4\u6f0f\u548c\u5806\u6808\u6ea2\u51fa\u7b49\u95ee\u9898\u3002<\/p>\n

\u6a21\u5f0f\uff1a<\/h3>\n

1. \u7f13\u5b58\u7ed3\u679c<\/strong><\/p>\n

\u5982\u679c\u60a8\u9700\u8981\u591a\u6b21\u8ba1\u7b97\u4e00\u4e2a\u503c\uff0c\u8bf7\u5c06\u5176\u5b58\u50a8\u5728\u53d8\u91cf\u4e2d\u5e76\u91cd\u590d\u4f7f\u7528\uff0c\u800c\u4e0d\u662f\u6bcf\u6b21\u90fd\u91cd\u65b0\u8ba1\u7b97\u3002<\/p>\n

\/\/ \u6a21\u5f0f\nString cachedValue = computeValue();<\/pre>\n
2. \u4f7f\u7528 StringBuilder<\/strong><\/p>\n
\u5f53\u60a8\u9700\u8981\u6784\u5efa\u4e00\u4e2a\u5b57\u7b26\u4e32\u65f6\uff0c\u8bf7\u4f7f\u7528 StringBuilder<\/code> \u800c\u4e0d\u662f\u5b57\u7b26\u4e32\u8fde\u63a5 (+)\uff0c\u56e0\u4e3a\u540e\u8005\u4f1a\u521b\u5efa\u4e00\u4e2a\u65b0\u5bf9\u8c61\u3002<\/p>\n
\/\/ \u6a21\u5f0f\nStringBuilder builder = new StringBuilder();\nbuilder.append(\"Hello\");\nbuilder.append(\"World\");\nString message = builder.toString();<\/pre>\n
3. \u907f\u514d\u91cd\u590d\u5f15\u7528<\/strong><\/p>\n
\u4fdd\u6301\u5bf9\u5bf9\u8c61\u7684\u5f15\u7528\uff0c\u76f4\u5230\u4e0d\u518d\u9700\u8981\u5b83\u4eec\uff0c\u907f\u514d\u521b\u5efa\u4e0d\u5fc5\u8981\u7684\u91cd\u590d\u5f15\u7528\u3002<\/p>\n
\/\/ \u6a21\u5f0f\nList<String> originalList = getSomeList();<\/pre>\n
\u53cd\u6a21\u5f0f\uff1a<\/h3>\n
1. \u5185\u5b58\u6cc4\u6f0f<\/strong><\/p>\n
\u5f53\u5bf9\u8c61\u4e0d\u518d\u9700\u8981\u65f6\uff0c\u4f46\u4ecd\u7136\u5b58\u5728\u5f15\u7528\u7684\u60c5\u51b5\u3002<\/p>\n
\/\/ \u53cd\u6a21\u5f0f\nHashMap<Integer, String> map = new HashMap<>();\nmap.put(1, \"John\");\nmap = null; \/\/ \u4ecd\u7136\u53ef\u4ee5\u901a\u8fc7 1 \u8bbf\u95ee John<\/pre>\n
2. \u6808\u6ea2\u51fa<\/strong><\/p>\n
\u5f53\u51fd\u6570\u8c03\u7528\u81ea\u8eab\u8fc7\u591a\u65f6\uff0c\u5bfc\u81f4\u5806\u6808\u7a7a\u95f4\u8017\u5c3d\u7684\u60c5\u51b5\u3002<\/p>\n
\/\/ \u53cd\u6a21\u5f0f\npublic static void recursiveMethod(int n) {\n  if (n <= 0) {\n    return;\n  }\n  recursiveMethod(n - 1);\n}<\/pre>\n
3. \u8fc7\u65e9\u4f18\u5316<\/strong><\/p>\n
\u5728\u786e\u5b9a\u4f18\u5316\u662f\u5fc5\u8981\u7684\u4e4b\u524d\uff0c\u4e0d\u8981\u5bf9\u4ee3\u7801\u8fdb\u884c\u4e0d\u5fc5\u8981\u7684\u4fee\u6539\u3002\u8fd9\u53ef\u80fd\u5bfc\u81f4\u4ee3\u7801\u53ef\u8bfb\u6027\u5dee\u548c\u610f\u5916\u884c\u4e3a\u3002<\/p>\n
\u5b9e\u6218\u6848\u4f8b\uff1a\u4f18\u5316\u6570\u636e\u67e5\u8be2<\/h2>\n
\u8003\u8651\u4e00\u4e2a\u51fd\u6570\uff0c\u8be5\u51fd\u6570\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u5927\u91cf\u6570\u636e\u5e76\u8fdb\u884c\u5904\u7406\u3002<\/p>\n
\u53cd\u6a21\u5f0f\uff1a<\/strong><\/p>\n
public List<Person> getPeople() {\n  List<Person> people = new ArrayList<>();\n  try (Connection connection = DriverManager.getConnection(...)) {\n    Statement statement = connection.createStatement();\n    ResultSet rs = statement.executeQuery(\"SELECT * FROM people\");\n    while (rs.next()) {\n      people.add(new Person(rs.getInt(1), rs.getString(2)));\n    }\n  } catch (Exception e) {\n    e.printStackTrace();\n  }\n  return people;\n}<\/pre>\n
\u6a21\u5f0f\uff1a<\/strong><\/p>\n
\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u6d41\u5904\u7406\u6765\u907f\u514d\u5728\u5185\u5b58\u4e2d\u5b58\u50a8\u6240\u6709\u6570\u636e\u3002<\/p>\n
public List<Person> getPeopleEfficiently() {\n  try (Connection connection = DriverManager.getConnection(...)) {\n    Statement statement = connection.createStatement();\n    ResultSet rs = statement.executeQuery(\"SELECT * FROM people\");\n    return rs.stream()\n      .map(r -> new Person(r.getInt(1), r.getString(2)))\n      .toList();\n  } catch (Exception e) {\n    e.printStackTrace();\n  }\n}<\/pre>\n
\u901a\u8fc7\u4f7f\u7528\u6d41\uff0c\u6211\u4eec\u53ef\u4ee5\u9010\u884c\u5904\u7406\u6570\u636e\uff0c\u4ece\u800c\u8282\u7701\u5185\u5b58\u7a7a\u95f4\u3002<\/p>\n
\u4eca\u5929\u5173\u4e8e\u300aJava\u51fd\u6570\u4e2d\u4f18\u5316\u5185\u5b58\u4f7f\u7528\u7684\u6a21\u5f0f\u548c\u53cd\u6a21\u5f0f\u300b\u7684\u5185\u5bb9\u4ecb\u7ecd\u5c31\u5230\u6b64\u7ed3\u675f\uff0c\u5982\u679c\u6709\u4ec0\u4e48\u7591\u95ee\u6216\u8005\u5efa\u8bae\uff0c\u53ef\u4ee5\u5728\u516c\u4f17\u53f7\u4e0b\u591a\u591a\u56de\u590d\u4ea4\u6d41\uff1b\u6587\u4e2d\u82e5\u6709\u4e0d\u6b63\u4e4b\u5904\uff0c\u4e5f\u5e0c\u671b\u56de\u590d\u7559\u8a00\u4ee5\u544a\u77e5\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
Java\u51fd\u6570\u4e2d\u4f18\u5316\u5185\u5b58\u4f7f\u7528\u7684\u6a21\u5f0f...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-202836","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202836","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=202836"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202836\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202836"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202836"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202836"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}