{"id":923260,"date":"2024-07-18T06:11:24","date_gmt":"2024-07-18T06:11:24","guid":{"rendered":"https:\/\/proxyelite.info\/?p=923260"},"modified":"2024-07-10T06:23:35","modified_gmt":"2024-07-10T06:23:35","slug":"mastering-the-java-8-stream-api-a-comprehensive-guide","status":"publish","type":"post","link":"https:\/\/proxyelite.info\/cn\/mastering-the-java-8-stream-api-a-comprehensive-guide\/","title":{"rendered":"\u638c\u63e1 Java 8 Stream API\uff1a\u7efc\u5408\u6307\u5357"},"content":{"rendered":"

\u4ec0\u4e48\u662f Java 8 Stream API \u4ee5\u53ca\u5b83\u5982\u4f55\u6539\u53d8\u60a8\u7684\u4ee3\u7801\uff1f<\/h3>\n\n\n\n

Java 8 Stream API \u6539\u53d8\u4e86 Java \u5f00\u53d1\u4eba\u5458\u7684\u683c\u5c40\uff0c\u63d0\u4f9b\u4e86\u4e00\u79cd\u4ee5\u58f0\u660e\u65b9\u5f0f\u9ad8\u6548\u5904\u7406\u6570\u636e\u7684\u65b0\u65b9\u6cd5\u3002\u672c\u6559\u7a0b\u5c06\u5f15\u5bfc\u60a8\u4e86\u89e3 Stream API \u7684\u6765\u9f99\u53bb\u8109\uff0c\u5e2e\u52a9\u60a8\u4e86\u89e3\u5176\u5f3a\u5927\u7684\u529f\u80fd\u4ee5\u53ca\u5982\u4f55\u5728\u4ee3\u7801\u4e2d\u5229\u7528\u5b83\u4eec\u3002<\/p>\n\n\n\n

\u76ee\u5f55<\/h3>\n\n\n\n
\u90e8\u5206<\/th>\u63cf\u8ff0<\/th><\/tr><\/thead>
\u4ecb\u7ecd<\/td>Java 8 Stream API \u6982\u8ff0<\/td><\/tr>
\u6d41\u521b\u5efa<\/td>\u521b\u5efa\u6d41\u7684\u4e0d\u540c\u65b9\u6cd5<\/td><\/tr>
\u4e2d\u7ea7\u64cd\u4f5c<\/td>\u5404\u79cd\u4e2d\u95f4\u64cd\u4f5c\u7684\u89e3\u91ca<\/td><\/tr>
\u7801\u5934\u8fd0\u8425<\/td>\u7ec8\u7aef\u64cd\u4f5c\u6982\u8ff0\u53ca\u5176\u5f71\u54cd<\/td><\/tr>
\u5e76\u884c\u6d41<\/td>\u5982\u4f55\u4f7f\u7528\u5e76\u884c\u6d41\u6765\u83b7\u5f97\u66f4\u597d\u7684\u6027\u80fd<\/td><\/tr>
\u5b9e\u9645\u4f8b\u5b50<\/td>\u6f14\u793a\u5982\u4f55\u4f7f\u7528 Stream API \u7684\u4ee3\u7801\u793a\u4f8b<\/td><\/tr>
\u4f7f\u7528 Stream API \u7684\u597d\u5904<\/td>Java\u5f00\u53d1\u4e2d\u4f7f\u7528Stream API\u7684\u4f18\u70b9<\/td><\/tr>
\u5e38\u89c1\u9677\u9631<\/td>\u5e38\u89c1\u9519\u8bef\u53ca\u907f\u514d\u65b9\u6cd5<\/td><\/tr>
\u7ed3\u8bba<\/td>\u8981\u70b9\u603b\u7ed3\u548c\u6700\u7ec8\u60f3\u6cd5<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u4ecb\u7ecd<\/h2>\n\n\n\n

Java 8 \u4e3a\u8be5\u8bed\u8a00\u5e26\u6765\u4e86\u8bb8\u591a\u65b0\u529f\u80fd\uff0c\u4f46\u5176\u4e2d\u5f71\u54cd\u6700\u5927\u7684\u662f Stream API\u3002\u6b64 API \u63d0\u4f9b\u4e86\u4e00\u79cd\u5904\u7406\u5143\u7d20\u5e8f\u5217\u7684\u51fd\u6570\u5f0f\u65b9\u6cd5\uff0c\u4f7f\u5f00\u53d1\u4eba\u5458\u80fd\u591f\u7f16\u5199\u66f4\u7b80\u6d01\u3001\u66f4\u6613\u8bfb\u7684\u4ee3\u7801\u3002\u6d41\u4e0d\u662f\u6570\u636e\u7ed3\u6784\uff1b\u5b83\u4eec\u662f\u5141\u8bb8\u60a8\u4ee5\u58f0\u660e\u65b9\u5f0f\u5904\u7406\u6570\u636e\u7684\u62bd\u8c61\u3002<\/p>\n\n\n\n

\u6d41\u521b\u5efa<\/h2>\n\n\n\n

\u53ef\u4ee5\u4ece\u5404\u79cd\u6570\u636e\u6e90\uff08\u4f8b\u5982\u96c6\u5408\u3001\u6570\u7ec4\u6216 I\/O \u901a\u9053\uff09\u521b\u5efa\u6d41\u3002\u4ee5\u4e0b\u662f\u521b\u5efa\u6d41\u7684\u4e00\u4e9b\u5e38\u89c1\u65b9\u6cd5\uff1a<\/p>\n\n\n\n

\u6765\u81ea\u6536\u85cf<\/h3>\n\n\n\n

\u60a8\u53ef\u4ee5\u4ece\u4efb\u4f55\u96c6\u5408\uff08\u4f8b\u5982\uff0c\u5217\u8868\u3001\u96c6\u5408\uff09\u521b\u5efa\u6d41\u3002<\/p>\n\n\n\n

List<String> list = Arrays.asList("a", "b", "c");\nStream<String> stream = list.stream();\n<\/code><\/pre><\/div>\n\n\n\n
\u6765\u81ea\u6570\u7ec4<\/h3>\n\n\n\n
\u60a8\u8fd8\u53ef\u4ee5\u4ece\u6570\u7ec4\u521b\u5efa\u6d41\u3002<\/p>\n\n\n\n
String[] array = {"a", "b", "c"};\nStream<String> stream = Arrays.stream(array);\n<\/code><\/pre><\/div>\n\n\n\n
\u6765\u81ea\u6587\u4ef6<\/h3>\n\n\n\n
Java NIO \u63d0\u4f9b\u4e86\u4e00\u79cd\u4ece\u6587\u4ef6\u521b\u5efa\u6d41\u7684\u65b9\u6cd5\u3002<\/p>\n\n\n\n
Stream<String> lines = Files.lines(Paths.get("file.txt"));\n<\/code><\/pre><\/div>\n\n\n\n
\u65e0\u9650\u6d41<\/h3>\n\n\n\n
\u60a8\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u65b9\u5f0f\u521b\u5efa\u65e0\u9650\u6d41 Stream.generate<\/code> \u6216\u8005 Stream.iterate<\/code>.<\/p>\n\n\n\n
Stream<Integer> infiniteStream = Stream.iterate(0, n -> n + 1);\n<\/code><\/pre><\/div>\n\n\n\n
\u4e2d\u7ea7\u64cd\u4f5c<\/h2>\n\n\n\n
\u4e2d\u95f4\u64cd\u4f5c\u4f1a\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u6d41\uff0c\u5e76\u4e14\u662f\u5ef6\u8fdf\u6267\u884c\u7684\uff0c\u8fd9\u610f\u5473\u7740\u5b83\u4eec\u76f4\u5230\u8c03\u7528\u7ec8\u7aef\u64cd\u4f5c\u65f6\u624d\u4f1a\u6267\u884c\u3002\u5b83\u4eec\u7528\u4e8e\u8f6c\u6362\u6216\u8fc7\u6ee4\u6570\u636e\u3002<\/p>\n\n\n\n
\u7b5b\u9009<\/h3>\n\n\n\n
\u6839\u636e\u6761\u4ef6\u8fc7\u6ee4\u5143\u7d20\u3002<\/p>\n\n\n\n
Stream<String> filteredStream = stream.filter(s -> s.startsWith("a"));\n<\/code><\/pre><\/div>\n\n\n\n
\u5730\u56fe<\/h3>\n\n\n\n
\u8f6c\u6362\u5143\u7d20\u3002<\/p>\n\n\n\n
Stream<Integer> lengthStream = stream.map(String::length);\n<\/code><\/pre><\/div>\n\n\n\n
\u5e73\u9762\u5730\u56fe<\/h3>\n\n\n\n
\u5c55\u5e73\u5d4c\u5957\u7ed3\u6784\u3002<\/p>\n\n\n\n
Stream<String> flatMappedStream = stream.flatMap(s -> Arrays.stream(s.split("")));\n<\/code><\/pre><\/div>\n\n\n\n
\u5df2\u6392\u5e8f<\/h3>\n\n\n\n
\u5bf9\u5143\u7d20\u8fdb\u884c\u6392\u5e8f\u3002<\/p>\n\n\n\n
Stream<String> sortedStream = stream.sorted();\n<\/code><\/pre><\/div>\n\n\n\n
\u6e05\u695a\u7684<\/h3>\n\n\n\n
\u5220\u9664\u91cd\u590d\u7684\u5143\u7d20\u3002<\/p>\n\n\n\n
Stream<String> distinctStream = stream.distinct();\n<\/code><\/pre><\/div>\n\n\n\n
\u9650\u5236\u548c\u8df3\u8fc7<\/h3>\n\n\n\n
\u5c06\u6d41\u622a\u65ad\u4e3a\u7ed9\u5b9a\u6570\u91cf\u7684\u5143\u7d20\u6216\u8df3\u8fc7\u524d n \u4e2a\u5143\u7d20\u3002<\/p>\n\n\n\n
Stream<String> limitedStream = stream.limit(2);\nStream<String> skippedStream = stream.skip(2);\n<\/code><\/pre><\/div>\n\n\n\n
\u7801\u5934\u8fd0\u8425<\/h2>\n\n\n\n
\u7ec8\u7aef\u64cd\u4f5c\u4f1a\u4ea7\u751f\u7ed3\u679c\u6216\u526f\u4f5c\u7528\uff0c\u5e76\u6807\u8bb0\u6d41\u5904\u7406\u7684\u7ed3\u675f\u3002\u4e00\u65e6\u6267\u884c\u4e86\u7ec8\u7aef\u64cd\u4f5c\uff0c\u6d41\u5c31\u4e0d\u80fd\u518d\u4f7f\u7528\u4e86\u3002<\/p>\n\n\n\n
forEach<\/h3>\n\n\n\n
\u9488\u5bf9\u6bcf\u4e2a\u5143\u7d20\u6267\u884c\u4e00\u4e2a\u64cd\u4f5c\u3002<\/p>\n\n\n\n
stream.forEach(System.out::println);\n<\/code><\/pre><\/div>\n\n\n\n
\u6536\u96c6<\/h3>\n\n\n\n
\u5c06\u6d41\u8f6c\u6362\u4e3a\u96c6\u5408\u6216\u5176\u4ed6\u6570\u636e\u7ed3\u6784\u3002<\/p>\n\n\n\n
List<String> list = stream.collect(Collectors.toList());\n<\/code><\/pre><\/div>\n\n\n\n
\u51cf\u5c11<\/h3>\n\n\n\n
\u5c06\u6d41\u51cf\u5c11\u4e3a\u5355\u4e2a\u503c\u3002<\/p>\n\n\n\n
Optional<String> concatenated = stream.reduce((s1, s2) -> s1 + s2);\n<\/code><\/pre><\/div>\n\n\n\n
\u6570\u6570<\/h3>\n\n\n\n
\u8fd4\u56de\u5143\u7d20\u7684\u6570\u91cf\u3002<\/p>\n\n\n\n
long count = stream.count();\n<\/code><\/pre><\/div>\n\n\n\n
\u5339\u914d\u64cd\u4f5c<\/h3>\n\n\n\n
\u68c0\u67e5\u662f\u5426\u6709\u4efb\u4f55\u5143\u7d20\u3001\u6240\u6709\u5143\u7d20\u6216\u6ca1\u6709\u5143\u7d20\u4e0e\u7ed9\u5b9a\u7684\u8c13\u8bcd\u5339\u914d\u3002<\/p>\n\n\n\n
boolean anyMatch = stream.anyMatch(s -> s.startsWith("a"));\nboolean allMatch = stream.allMatch(s -> s.length() > 1);\nboolean noneMatch = stream.noneMatch(s -> s.isEmpty());\n<\/code><\/pre><\/div>\n\n\n\n
\u67e5\u627e\u7b2c\u4e00\u4e2a\u548c\u67e5\u627e\u4efb\u610f<\/h3>\n\n\n\n
\u8fd4\u56de\u6d41\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u6216\u4efb\u610f\u5143\u7d20\u3002<\/p>\n\n\n\n
Optional<String> first = stream.findFirst();\nOptional<String> any = stream.findAny();\n<\/code><\/pre><\/div>\n\n\n\n
\u5e76\u884c\u6d41<\/h2>\n\n\n\n
\u6d41\u53ef\u4ee5\u8f7b\u677e\u8f6c\u6362\u4e3a\u5e76\u884c\u6d41\uff0c\u4ee5\u5229\u7528\u591a\u6838\u5904\u7406\u5668\u5e76\u540c\u65f6\u6267\u884c\u64cd\u4f5c\u3002<\/p>\n\n\n\n
Stream<String> parallelStream = list.parallelStream();\n<\/code><\/pre><\/div>\n\n\n\n
\u5e76\u884c\u6d41\u53ef\u4ee5\u663e\u8457\u63d0\u9ad8\u5927\u578b\u6570\u636e\u96c6\u7684\u6027\u80fd\uff0c\u4f46\u5e94\u8c28\u614e\u4f7f\u7528\u4ee5\u907f\u514d\u5e76\u53d1\u95ee\u9898\u3002<\/p>\n\n\n\n
\u5b9e\u9645\u4f8b\u5b50<\/h2>\n\n\n\n
\u793a\u4f8b 1\uff1a\u8fc7\u6ee4\u548c\u6536\u96c6<\/h3>\n\n\n\n
\u8ba9\u6211\u4eec\u8fc7\u6ee4\u4e00\u4e2a\u5b57\u7b26\u4e32\u5217\u8868\u4ee5\u67e5\u627e\u4ee5\u201ca\u201d\u5f00\u5934\u7684\u5b57\u7b26\u4e32\u5e76\u5c06\u5b83\u4eec\u6536\u96c6\u5230\u4e00\u4e2a\u65b0\u5217\u8868\u4e2d\u3002<\/p>\n\n\n\n
List<String> result = list.stream()\n    .filter(s -> s.startsWith("a"))\n    .collect(Collectors.toList());\n<\/code><\/pre><\/div>\n\n\n\n
\u793a\u4f8b 2\uff1aMap \u548c Reduce<\/h3>\n\n\n\n
\u5c06\u5b57\u7b26\u4e32\u5217\u8868\u8f6c\u6362\u4e3a\u5927\u5199\u5e76\u5c06\u5b83\u4eec\u8fde\u63a5\u8d77\u6765\u3002<\/p>\n\n\n\n
Optional<String> result = list.stream()\n    .map(String::toUpperCase)\n    .reduce((s1, s2) -> s1 + s2);\n<\/code><\/pre><\/div>\n\n\n\n
\u793a\u4f8b 3\uff1a\u6392\u5e8f\u548c\u9650\u5236<\/h3>\n\n\n\n
\u5bf9\u5b57\u7b26\u4e32\u5217\u8868\u8fdb\u884c\u6392\u5e8f\u5e76\u83b7\u53d6\u524d 3 \u4e2a\u5143\u7d20\u3002<\/p>\n\n\n\n
List<String> result = list.stream()\n    .sorted()\n    .limit(3)\n    .collect(Collectors.toList());\n<\/code><\/pre><\/div>\n\n\n\n
\u4f7f\u7528 Stream API \u7684\u597d\u5904<\/h2>\n\n\n\n
\u7b80\u6d01\u7684\u4ee3\u7801<\/h3>\n\n\n\n
Stream API \u53ef\u5b9e\u73b0\u66f4\u7b80\u6d01\u3001\u66f4\u6613\u8bfb\u7684\u4ee3\u7801\u3002\u8fc7\u53bb\u9700\u8981\u591a\u884c\u548c\u5faa\u73af\u7684\u64cd\u4f5c\u901a\u5e38\u53ef\u4ee5\u7b80\u5316\u4e3a\u4e00\u884c\u3002<\/p>\n\n\n\n
\u63d0\u9ad8\u6027\u80fd<\/h3>\n\n\n\n
\u51ed\u501f\u5e76\u884c\u5904\u7406\u6570\u636e\u7684\u80fd\u529b\uff0cStream API \u53ef\u4ee5\u663e\u8457\u63d0\u9ad8\u5927\u578b\u6570\u636e\u96c6\u7684\u6027\u80fd\u3002<\/p>\n\n\n\n
\u51fd\u6570\u5f0f\u7f16\u7a0b\u8303\u5f0f<\/h3>\n\n\n\n
Stream API \u5c06\u51fd\u6570\u5f0f\u7f16\u7a0b\u6982\u5ff5\u5f15\u5165 Java\uff0c\u4f7f\u5f97\u4ee5\u66f4\u5177\u58f0\u660e\u6027\u7684\u65b9\u5f0f\u6267\u884c\u590d\u6742\u7684\u6570\u636e\u64cd\u4f5c\u53d8\u5f97\u66f4\u52a0\u5bb9\u6613\u3002<\/p>\n\n\n\n
\u5e38\u89c1\u9677\u9631<\/h2>\n\n\n\n
\u53ef\u53d8\u6027<\/h3>\n\n\n\n
\u907f\u514d\u5728\u4e2d\u95f4\u64cd\u4f5c\u4e2d\u4fee\u6539\u6d41\u7684\u6e90\uff0c\u56e0\u4e3a\u8fd9\u53ef\u80fd\u5bfc\u81f4\u4e0d\u53ef\u9884\u6d4b\u7684\u884c\u4e3a\u3002<\/p>\n\n\n\n
\u5e76\u884c\u6d41<\/h3>\n\n\n\n
\u8c28\u614e\u4f7f\u7528\u5e76\u884c\u6d41\uff0c\u56e0\u4e3a\u5b83\u4eec\u53ef\u80fd\u4f1a\u5f15\u5165\u5e76\u53d1\u95ee\u9898\uff0c\u5e76\u4e14\u53ef\u80fd\u5e76\u4e0d\u603b\u80fd\u5e26\u6765\u6027\u80fd\u63d0\u5347\u3002<\/p>\n\n\n\n
\u60f0\u6027\u6c42\u503c<\/h3>\n\n\n\n
\u8bf7\u8bb0\u4f4f\uff0c\u4e2d\u95f4\u64cd\u4f5c\u662f\u60f0\u6027\u7684\u3002\u8bf7\u786e\u4fdd\u8c03\u7528\u7ec8\u7aef\u64cd\u4f5c\u6765\u89e6\u53d1\u5904\u7406\u3002<\/p>\n\n\n\n
\u7ed3\u8bba<\/h2>\n\n\n\n
Java 8 Stream API \u662f\u4e00\u6b3e\u529f\u80fd\u5f3a\u5927\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u6539\u53d8\u60a8\u7f16\u5199 Java \u4ee3\u7801\u7684\u65b9\u5f0f\u3002\u901a\u8fc7\u63d0\u4f9b\u6570\u636e\u5904\u7406\u7684\u529f\u80fd\u65b9\u6cd5\uff0c\u5b83\u5141\u8bb8\u7f16\u5199\u66f4\u7b80\u6d01\u3001\u53ef\u8bfb\u548c\u9ad8\u6548\u7684\u4ee3\u7801\u3002\u65e0\u8bba\u60a8\u662f\u8fc7\u6ee4\u3001\u8f6c\u6362\u8fd8\u662f\u805a\u5408\u6570\u636e\uff0cStream API \u90fd\u80fd\u63d0\u4f9b\u7075\u6d3b\u800c\u5f3a\u5927\u7684\u89e3\u51b3\u65b9\u6848\u3002\u4e0e\u4efb\u4f55\u5de5\u5177\u4e00\u6837\uff0c\u4e86\u89e3\u5176\u529f\u80fd\u548c\u5c40\u9650\u6027\u5bf9\u4e8e\u6709\u6548\u4f7f\u7528\u5b83\u975e\u5e38\u91cd\u8981\u3002<\/p>\n\n\n\n
\u5728\u60a8\u7684\u9879\u76ee\u4e2d\u63a2\u7d22 Stream API\uff0c\u5e76\u4f53\u9a8c\u66f4\u73b0\u4ee3\u3001\u66f4\u5b9e\u7528\u7684 Java \u7f16\u7a0b\u65b9\u6cd5\u5e26\u6765\u7684\u597d\u5904\u3002<\/p>","protected":false},"excerpt":{"rendered":"
What is the Java 8 Stream API and How Can It Transform Your Code? The Java 8 Stream API is a game-changer for Java developers, offering a new way to process data declaratively and efficiently. This tutorial will guide you through the ins and outs of the Stream API, helping you understand its powerful features […]<\/p>\n","protected":false},"author":1,"featured_media":923261,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-923260","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles"],"acf":[],"_links":{"self":[{"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/posts\/923260","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/comments?post=923260"}],"version-history":[{"count":1,"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/posts\/923260\/revisions"}],"predecessor-version":[{"id":923262,"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/posts\/923260\/revisions\/923262"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/media\/923261"}],"wp:attachment":[{"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/media?parent=923260"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/categories?post=923260"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/proxyelite.info\/cn\/wp-json\/wp\/v2\/tags?post=923260"}],"curies":[{"name":"\u53ef\u6e7f\u6027\u7c89\u5242","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}