{"id":18332,"date":"2025-07-05T19:59:27","date_gmt":"2025-07-05T11:59:27","guid":{"rendered":"https:\/\/92it.top\/?p=18332"},"modified":"2025-07-05T19:59:27","modified_gmt":"2025-07-05T11:59:27","slug":"java-stream-%e6%b5%81%ef%bc%9a%e8%ae%a9%e4%bb%a3%e7%a0%81%e6%9b%b4%e4%bc%98%e9%9b%85%e7%9a%84%e5%88%a9%e5%99%a8","status":"publish","type":"post","link":"https:\/\/92it.top\/?p=18332","title":{"rendered":"Java Stream \u6d41\uff1a\u8ba9\u4ee3\u7801\u66f4\u4f18\u96c5\u7684\u5229\u5668"},"content":{"rendered":"\n

\u8f6c\u8f7d\uff1aJava Stream \u6d41\uff1a\u8ba9\u4ee3\u7801\u66f4\u4f18\u96c5\u7684\u5229\u5668<\/a><\/p>\n\n\n\n

\u5728\u65e5\u5e38\u5f00\u53d1\u4e2d\uff0c\u4f60\u662f\u5426\u7ecf\u5e38\u9047\u5230\u9700\u8981\u5904\u7406\u96c6\u5408\u6570\u636e\u7684\u573a\u666f\uff1f\u662f\u5426\u538c\u5026\u4e86\u5199\u5927\u91cf\u7684 for \u5faa\u73af\uff1f\u4eca\u5929\uff0c\u8ba9\u6211\u4eec\u4e00\u8d77\u63a2\u7d22 Java Stream \u6d41\uff0c\u8fd9\u4e2a\u8ba9\u4ee3\u7801\u66f4\u4f18\u96c5\u3001\u66f4\u7b80\u6d01\u7684\u5f3a\u5927\u5de5\u5177\u3002<\/p>\n\n\n\n

\u4e00\u3001Stream \u6d41\u662f\u4ec0\u4e48\uff1f<\/strong><\/p>\n\n\n\n

\n\n\n\n

Stream \u662f Java 8 \u5f15\u5165\u7684\u4e00\u4e2a\u65b0\u7279\u6027\uff0c\u5b83\u5141\u8bb8\u6211\u4eec\u4ee5\u58f0\u660e\u5f0f\u7684\u65b9\u5f0f\u5904\u7406\u6570\u636e\u96c6\u5408\u3002\u60f3\u8c61\u4e00\u4e0b\uff0c\u6570\u636e\u5c31\u50cf\u4e00\u6761\u6cb3\u6d41\uff0c\u6211\u4eec\u53ef\u4ee5\u5728\u8fd9\u6761\u6cb3\u6d41\u4e0a\u8fdb\u884c\u5404\u79cd\u64cd\u4f5c\uff0c\u6bd4\u5982\u8fc7\u6ee4\u3001\u8f6c\u6362\u3001\u805a\u5408\u7b49\u3002<\/p>\n\n\n\n

\/\/ \u4f20\u7edf\u65b9\u5f0f\nList<String> filteredList = new ArrayList<>();\nfor (String str : list) {\n    if (str.length() > 5) {\n        filteredList.add(str);\n    }\n}\n\n\/\/ Stream \u65b9\u5f0f\nList<String> filteredList = list.stream()\n    .filter(str -> str.length() > 5)\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
 \u3000<\/p>\n\n\n\n
\u4e8c\u3001Stream \u6d41\u7684\u521b\u5efa\u65b9\u5f0f<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u5728 Java \u4e2d\uff0c\u6709\u591a\u79cd\u65b9\u5f0f\u53ef\u4ee5\u521b\u5efa Stream \u6d41\u3002\u9009\u62e9\u5408\u9002\u7684\u65b9\u5f0f\u53d6\u51b3\u4e8e\u4f60\u7684\u6570\u636e\u6e90\u7c7b\u578b\u548c\u5177\u4f53\u9700\u6c42\u3002<\/p>\n\n\n\n
    \n
  • 1. \u4ece\u96c6\u5408\u521b\u5efa<\/strong><\/li>\n<\/ul>\n\n\n\n
    \u4ece\u96c6\u5408\u521b\u5efa Stream \u662f\u6700\u5e38\u7528\u7684\u65b9\u5f0f\u4e4b\u4e00\u3002Java 8 \u4e3a Collection \u63a5\u53e3\u6dfb\u52a0\u4e86 stream() \u65b9\u6cd5\uff0c\u53ef\u4ee5\u65b9\u4fbf\u5730\u5c06\u96c6\u5408\u8f6c\u6362\u4e3a\u6d41\u3002<\/p>\n\n\n\n
    List<String> list = Arrays.asList(\"Java\", \"Python\", \"Go\");\nStream<String> stream = list.stream();<\/pre>\n\n\n\n
    \u3000<\/p>\n\n\n\n
      \n
    • 2. \u4ece\u6570\u7ec4\u521b\u5efa<\/strong><\/li>\n<\/ul>\n\n\n\n
      \u5bf9\u4e8e\u6570\u7ec4\u7c7b\u578b\u7684\u6570\u636e\uff0c\u53ef\u4ee5\u4f7f\u7528 Arrays.stream() \u65b9\u6cd5\u521b\u5efa\u6d41\u3002\u8fd9\u79cd\u65b9\u5f0f\u7279\u522b\u9002\u5408\u5904\u7406\u57fa\u672c\u7c7b\u578b\u6570\u7ec4\u3002<\/p>\n\n\n\n
      String[] array = {\"Java\", \"Python\", \"Go\"};\nStream<String> stream = Arrays.stream(array);\n\n\/\/ \u5904\u7406\u57fa\u672c\u7c7b\u578b\u6570\u7ec4\nint[] numbers = {1, 2, 3, 4, 5};\nIntStream intStream = Arrays.stream(numbers);<\/pre>\n\n\n\n
      \u3000<\/p>\n\n\n\n
        \n
      • 3. \u4f7f\u7528 Stream.of()<\/strong><\/li>\n<\/ul>\n\n\n\n
        Stream.of() \u65b9\u6cd5\u53ef\u4ee5\u63a5\u53d7\u4efb\u610f\u6570\u91cf\u7684\u53c2\u6570\uff0c\u521b\u5efa\u4e00\u4e2a\u5305\u542b\u8fd9\u4e9b\u5143\u7d20\u7684\u6d41\u3002\u8fd9\u79cd\u65b9\u5f0f\u9002\u5408\u521b\u5efa\u5305\u542b\u5c11\u91cf\u5143\u7d20\u7684\u6d41\u3002<\/p>\n\n\n\n
        Stream<String> stream = Stream.of(\"Java\", \"Python\", \"Go\");\n\n\/\/ \u4e5f\u53ef\u4ee5\u521b\u5efa\u57fa\u672c\u7c7b\u578b\u7684\u6d41\nIntStream intStream = IntStream.of(1, 2, 3, 4, 5);\nDoubleStream doubleStream = DoubleStream.of(1.0, 2.0, 3.0);<\/pre>\n\n\n\n
        \u3000<\/p>\n\n\n\n
          \n
        • 4. \u4f7f\u7528 Stream.iterate() \u521b\u5efa\u65e0\u9650\u6d41<\/strong><\/li>\n<\/ul>\n\n\n\n
          Stream.iterate() \u65b9\u6cd5\u53ef\u4ee5\u521b\u5efa\u65e0\u9650\u6d41\uff0c\u5b83\u63a5\u53d7\u4e00\u4e2a\u521d\u59cb\u503c\u548c\u4e00\u4e2a\u51fd\u6570\uff0c\u901a\u8fc7\u4e0d\u65ad\u5e94\u7528\u8fd9\u4e2a\u51fd\u6570\u6765\u751f\u6210\u6d41\u4e2d\u7684\u5143\u7d20\u3002\u901a\u5e38\u9700\u8981\u914d\u5408 limit() \u65b9\u6cd5\u6765\u9650\u5236\u6d41\u7684\u957f\u5ea6\u3002<\/p>\n\n\n\n
          \/\/ \u751f\u6210\u524d10\u4e2a\u5076\u6570\nStream<Integer> stream = Stream.iterate(0, n -> n + 2)\n    .limit(10);\n\n\/\/ \u751f\u6210\u6590\u6ce2\u90a3\u5951\u6570\u5217\nStream<Long> fibonacci = Stream.iterate(\n    new long[]{0, 1},\n    f -> new long[]{f[1], f[0] + f[1]}\n).map(f -> f[0])\n .limit(10);<\/pre>\n\n\n\n
          \u3000<\/p>\n\n\n\n
            \n
          • 5. \u4f7f\u7528 Stream.generate() \u521b\u5efa\u65e0\u9650\u6d41<\/strong><\/li>\n<\/ul>\n\n\n\n
            Stream.generate() \u65b9\u6cd5\u63a5\u53d7\u4e00\u4e2a Supplier \u51fd\u6570\u5f0f\u63a5\u53e3\uff0c\u7528\u4e8e\u751f\u6210\u6d41\u4e2d\u7684\u5143\u7d20\u3002\u4e0e iterate() \u4e0d\u540c\uff0cgenerate() \u751f\u6210\u7684\u6bcf\u4e2a\u5143\u7d20\u90fd\u662f\u72ec\u7acb\u7684\u3002<\/p>\n\n\n\n
            \/ \u751f\u6210\u968f\u673a\u6570\u6d41\nStream<Double> randomStream = Stream.generate(Math::random)\n    .limit(5);\n\n\/\/ \u751f\u6210\u5e38\u91cf\u6d41\nStream<String> constantStream = Stream.generate(() -> \"constant\")\n    .limit(3);<\/pre>\n\n\n\n
            \u3000<\/p>\n\n\n\n
              \n
            • 6. \u4ece\u6587\u4ef6\u521b\u5efa\u6d41<\/strong><\/li>\n<\/ul>\n\n\n\n
              Java 8 \u63d0\u4f9b\u4e86 Files.lines() \u65b9\u6cd5\uff0c\u53ef\u4ee5\u65b9\u4fbf\u5730\u4ece\u6587\u4ef6\u4e2d\u521b\u5efa\u6d41\uff0c\u6bcf\u884c\u6587\u672c\u4f5c\u4e3a\u6d41\u4e2d\u7684\u4e00\u4e2a\u5143\u7d20\u3002<\/p>\n\n\n\n
              \/ \u8bfb\u53d6\u6587\u4ef6\u5185\u5bb9\ntry (Stream<String> lines = Files.lines(Paths.get(\"file.txt\"))) {\n    lines.forEach(System.out::println);\n} catch (IOException e) {\n    e.printStackTrace();\n}<\/pre>\n\n\n\n
              \u3000<\/p>\n\n\n\n
                \n
              • 7. \u4ece\u5b57\u7b26\u4e32\u521b\u5efa\u6d41<\/strong><\/li>\n<\/ul>\n\n\n\n
                \u53ef\u4ee5\u4f7f\u7528 Pattern.splitAsStream() \u65b9\u6cd5\u5c06\u5b57\u7b26\u4e32\u5206\u5272\u6210\u6d41\u3002<\/p>\n\n\n\n
                \/\/ \u5c06\u5b57\u7b26\u4e32\u6309\u7a7a\u683c\u5206\u5272\u6210\u6d41\nStream<String> words = Pattern.compile(\"\\\\s+\")\n    .splitAsStream(\"Java Python Go\");<\/pre>\n\n\n\n
                \u3000<\/p>\n\n\n\n
                  \n
                • 8. \u4ece Stream.Builder \u521b\u5efa\u6d41<\/strong><\/li>\n<\/ul>\n\n\n\n
                  Stream.Builder \u63d0\u4f9b\u4e86\u66f4\u7075\u6d3b\u7684\u65b9\u5f0f\u6765\u6784\u5efa\u6d41\uff0c\u7279\u522b\u9002\u5408\u5728\u5faa\u73af\u4e2d\u52a8\u6001\u6dfb\u52a0\u5143\u7d20\u3002<\/p>\n\n\n\n
                  Stream.Builder<String> builder = Stream.builder();\nbuilder.add(\"Java\")\n       .add(\"Python\")\n       .add(\"Go\");\nStream<String> stream = builder.build();<\/pre>\n\n\n\n
                  \u3000<\/p>\n\n\n\n
                    \n
                  • 9. \u4ece Optional \u521b\u5efa\u6d41<\/strong><\/li>\n<\/ul>\n\n\n\n
                    Java 9 \u5f15\u5165\u4e86 Optional.stream() \u65b9\u6cd5\uff0c\u53ef\u4ee5\u5c06 Optional \u8f6c\u6362\u4e3a\u6d41\u3002<\/p>\n\n\n\n
                    Optional<String> optional = Optional.of(\"Java\");\nStream<String> stream = optional.stream();<\/pre>\n\n\n\n
                    \u3000<\/p>\n\n\n\n
                      \n
                    • 10. \u4ece\u8fed\u4ee3\u5668\u521b\u5efa\u6d41<\/strong><\/li>\n<\/ul>\n\n\n\n
                      \u53ef\u4ee5\u4f7f\u7528 StreamSupport.stream() \u65b9\u6cd5\u4ece\u8fed\u4ee3\u5668\u521b\u5efa\u6d41\u3002<\/p>\n\n\n\n
                      Iterator<String> iterator = Arrays.asList(\"Java\", \"Python\", \"Go\").iterator();\nStream<String> stream = StreamSupport.stream(\n    Spliterators.spliteratorUnknownSize(iterator, Spliterator.ORDERED),\n    false\n);<\/pre>\n\n\n\n
                      \u3000<\/p>\n\n\n\n
                      \u4e09\u3001Stream \u6d41\u7684\u64cd\u4f5c\u7c7b\u578b<\/strong><\/p>\n\n\n\n
                      \n\n\n\n
                      1. \u4e2d\u95f4\u64cd\u4f5c\uff08Intermediate Operations\uff09<\/strong><\/p>\n\n\n\n
                      \u4e2d\u95f4\u64cd\u4f5c\u4f1a\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684 Stream\uff0c\u5141\u8bb8\u6211\u4eec\u7ee7\u7eed\u5bf9\u6570\u636e\u8fdb\u884c\u5904\u7406\u3002\u8fd9\u4e9b\u64cd\u4f5c\u662f\u60f0\u6027\u7684\uff0c\u53ea\u6709\u5728\u6267\u884c\u7ec8\u7aef\u64cd\u4f5c\u65f6\u624d\u4f1a\u771f\u6b63\u6267\u884c\u3002<\/p>\n\n\n\n
                      \u3000<\/p>\n\n\n\n
                        \n
                      • 1.1 filter\uff1a\u8fc7\u6ee4<\/li>\n<\/ul>\n\n\n\n
                        filter \u64cd\u4f5c\u7528\u4e8e\u6839\u636e\u6761\u4ef6\u7b5b\u9009\u5143\u7d20\uff0c\u53ea\u4fdd\u7559\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7d20\u3002\u5b83\u63a5\u6536\u4e00\u4e2a Predicate \u51fd\u6570\u5f0f\u63a5\u53e3\u4f5c\u4e3a\u53c2\u6570\uff0c\u8fd4\u56de\u4e00\u4e2a\u5e03\u5c14\u503c\u3002<\/p>\n\n\n\n
                        List<String> longWords = words.stream()\n    .filter(word -> word.length() > 5)\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                        \u3000<\/p>\n\n\n\n
                          \n
                        • 1.2 map\uff1a\u8f6c\u6362<\/li>\n<\/ul>\n\n\n\n
                          map \u64cd\u4f5c\u7528\u4e8e\u5c06\u6d41\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u8f6c\u6362\u4e3a\u53e6\u4e00\u4e2a\u5143\u7d20\u3002\u5b83\u63a5\u6536\u4e00\u4e2a Function \u51fd\u6570\u5f0f\u63a5\u53e3\u4f5c\u4e3a\u53c2\u6570\uff0c\u53ef\u4ee5\u5c06\u4e00\u79cd\u7c7b\u578b\u8f6c\u6362\u4e3a\u53e6\u4e00\u79cd\u7c7b\u578b\u3002<\/p>\n\n\n\n
                          List<Integer> lengths = words.stream()\n    .map(String::length)\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                          \u3000<\/p>\n\n\n\n
                            \n
                          • 1.3 flatMap\uff1a\u6241\u5e73\u5316<\/li>\n<\/ul>\n\n\n\n
                            flatMap \u64cd\u4f5c\u7528\u4e8e\u5c06\u6d41\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u8f6c\u6362\u4e3a\u53e6\u4e00\u4e2a\u6d41\uff0c\u7136\u540e\u5c06\u6240\u6709\u6d41\u5408\u5e76\u4e3a\u4e00\u4e2a\u6d41\u3002\u5b83\u7279\u522b\u9002\u7528\u4e8e\u5904\u7406\u5d4c\u5957\u96c6\u5408\u6216\u9700\u8981\u5c55\u5f00\u7684\u6570\u636e\u7ed3\u6784\u3002<\/p>\n\n\n\n
                            List<String> allWords = sentences.stream()\n    .flatMap(sentence -> Arrays.stream(sentence.split(\" \")))\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                            \u3000<\/p>\n\n\n\n
                              \n
                            • 1.4 distinct\uff1a\u53bb\u91cd<\/li>\n<\/ul>\n\n\n\n
                              distinct \u64cd\u4f5c\u7528\u4e8e\u53bb\u9664\u6d41\u4e2d\u7684\u91cd\u590d\u5143\u7d20\uff0c\u57fa\u4e8e\u5143\u7d20\u7684 equals() \u65b9\u6cd5\u8fdb\u884c\u5224\u65ad\u3002\u5b83\u5bf9\u4e8e\u9700\u8981\u552f\u4e00\u503c\u7684\u573a\u666f\u975e\u5e38\u6709\u7528\u3002<\/p>\n\n\n\n
                              List<String> uniqueWords = words.stream()\n    .distinct()\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                              \u3000<\/p>\n\n\n\n
                                \n
                              • 1.5 sorted\uff1a\u6392\u5e8f<\/li>\n<\/ul>\n\n\n\n
                                sorted \u64cd\u4f5c\u7528\u4e8e\u5bf9\u6d41\u4e2d\u7684\u5143\u7d20\u8fdb\u884c\u6392\u5e8f\u3002\u5b83\u53ef\u4ee5\u4f7f\u7528\u81ea\u7136\u6392\u5e8f\uff08\u5143\u7d20\u5fc5\u987b\u5b9e\u73b0 Comparable \u63a5\u53e3\uff09\u6216\u81ea\u5b9a\u4e49\u6bd4\u8f83\u5668\u3002<\/p>\n\n\n\n
                                List<String> sortedWords = words.stream()\n    .sorted()\n    .collect(Collectors.toList());\n\n\/\/ \u81ea\u5b9a\u4e49\u6392\u5e8f\nList<String> customSorted = words.stream()\n    .sorted((a, b) -> b.length() - a.length())\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                                \u3000<\/p>\n\n\n\n
                                  \n
                                • 1.6 peek\uff1a\u8c03\u8bd5<\/li>\n<\/ul>\n\n\n\n
                                  peek \u64cd\u4f5c\u7528\u4e8e\u67e5\u770b\u6d41\u4e2d\u7684\u5143\u7d20\uff0c\u901a\u5e38\u7528\u4e8e\u8c03\u8bd5\u76ee\u7684\u3002\u5b83\u63a5\u6536\u4e00\u4e2a Consumer \u51fd\u6570\u5f0f\u63a5\u53e3\uff0c\u53ef\u4ee5\u5bf9\u6bcf\u4e2a\u5143\u7d20\u6267\u884c\u64cd\u4f5c\u800c\u4e0d\u6539\u53d8\u6d41\u7684\u5185\u5bb9\u3002<\/p>\n\n\n\n
                                  List<String> result = words.stream()\n    .filter(word -> word.length() > 5)\n    .peek(word -> System.out.println(\"\u8fc7\u6ee4\u540e\u7684\u5355\u8bcd: \" + word))\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                                  \u3000<\/p>\n\n\n\n
                                  2. \u7ec8\u7aef\u64cd\u4f5c\uff08Terminal Operations\uff09<\/strong><\/p>\n\n\n\n
                                  \u7ec8\u7aef\u64cd\u4f5c\u4f1a\u6d88\u8017\u6d41\u5e76\u4ea7\u751f\u4e00\u4e2a\u7ed3\u679c\u6216\u526f\u4f5c\u7528\u3002\u6267\u884c\u7ec8\u7aef\u64cd\u4f5c\u540e\uff0c\u6d41\u5c31\u4e0d\u80fd\u518d\u88ab\u4f7f\u7528\u3002<\/p>\n\n\n\n
                                  \u3000<\/p>\n\n\n\n
                                    \n
                                  • 2.1 collect\uff1a\u6536\u96c6<\/li>\n<\/ul>\n\n\n\n
                                    collect \u64cd\u4f5c\u7528\u4e8e\u5c06\u6d41\u4e2d\u7684\u5143\u7d20\u6536\u96c6\u5230\u4e0d\u540c\u7684\u96c6\u5408\u4e2d\u3002\u5b83\u662f\u6700\u5e38\u7528\u7684\u7ec8\u7aef\u64cd\u4f5c\u4e4b\u4e00\uff0c\u53ef\u4ee5\u6536\u96c6\u5230 List\u3001Set\u3001Map \u7b49\u96c6\u5408\u4e2d\u3002<\/p>\n\n\n\n
                                    \/\/ \u6536\u96c6\u5230List\nList<String> list = stream.collect(Collectors.toList());\n\n\/\/ \u6536\u96c6\u5230Set\nSet<String> set = stream.collect(Collectors.toSet());\n\n\/\/ \u6536\u96c6\u5230Map\nMap<String, Integer> map = stream.collect(\n    Collectors.toMap(\n        word -> word,\n        String::length\n    )\n);<\/pre>\n\n\n\n
                                    \u3000\u3000<\/p>\n\n\n\n
                                      \n
                                    • 2.2 reduce\uff1a\u5f52\u7ea6<\/li>\n<\/ul>\n\n\n\n
                                      reduce \u64cd\u4f5c\u7528\u4e8e\u5c06\u6d41\u4e2d\u7684\u5143\u7d20\u7ec4\u5408\u8d77\u6765\uff0c\u4ea7\u751f\u4e00\u4e2a\u5355\u4e00\u7684\u7ed3\u679c\u3002\u5b83\u7279\u522b\u9002\u7528\u4e8e\u6c42\u548c\u3001\u6c42\u79ef\u3001\u627e\u51fa\u6700\u5927\u503c\u7b49\u805a\u5408\u64cd\u4f5c\u3002<\/p>\n\n\n\n
                                      \/\/ \u6c42\u548c\nint sum = numbers.stream()\n    .reduce(0, Integer::sum);\n\n\/\/ \u627e\u51fa\u6700\u957f\u7684\u5355\u8bcd\nOptional<String> longest = words.stream()\n    .reduce((a, b) -> a.length() > b.length() ? a : b);<\/pre>\n\n\n\n
                                      \u3000\u3000<\/p>\n\n\n\n
                                        \n
                                      • 2.3 forEach\uff1a\u904d\u5386<\/li>\n<\/ul>\n\n\n\n
                                        forEach \u64cd\u4f5c\u7528\u4e8e\u904d\u5386\u6d41\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u5e76\u6267\u884c\u64cd\u4f5c\u3002\u5b83\u901a\u5e38\u7528\u4e8e\u6253\u5370\u7ed3\u679c\u6216\u6267\u884c\u5176\u4ed6\u526f\u4f5c\u7528\u64cd\u4f5c\u3002<\/p>\n\n\n\n
                                        words.stream()\n    .forEach(System.out::println);<\/pre>\n\n\n\n
                                        \u3000\u3000\u3000<\/p>\n\n\n\n
                                          \n
                                        • 2.4 anyMatch\/allMatch\/noneMatch\uff1a\u5339\u914d<\/li>\n<\/ul>\n\n\n\n
                                          \u8fd9\u4e9b\u64cd\u4f5c\u7528\u4e8e\u68c0\u67e5\u6d41\u4e2d\u7684\u5143\u7d20\u662f\u5426\u6ee1\u8db3\u7279\u5b9a\u6761\u4ef6\uff1a<\/p>\n\n\n\n
                                            \n
                                          • \u2022 anyMatch\uff1a\u68c0\u67e5\u662f\u5426\u5b58\u5728\u81f3\u5c11\u4e00\u4e2a\u5143\u7d20\u6ee1\u8db3\u6761\u4ef6<\/li>\n\n\n\n
                                          • \u2022 allMatch\uff1a\u68c0\u67e5\u662f\u5426\u6240\u6709\u5143\u7d20\u90fd\u6ee1\u8db3\u6761\u4ef6<\/li>\n\n\n\n
                                          • \u2022 noneMatch\uff1a\u68c0\u67e5\u662f\u5426\u6ca1\u6709\u5143\u7d20\u6ee1\u8db3\u6761\u4ef6<\/li>\n<\/ul>\n\n\n\n
                                            boolean hasLongWord = words.stream()\n    .anyMatch(word -> word.length() > 10);\n\nboolean allLongWords = words.stream()\n    .allMatch(word -> word.length() > 5);\n\nboolean noShortWords = words.stream()\n    .noneMatch(word -> word.length() < 3);<\/pre>\n\n\n\n
                                            \u3000<\/p>\n\n\n\n
                                              \n
                                            • 2.5 findFirst\/findAny\uff1a\u67e5\u627e<\/li>\n<\/ul>\n\n\n\n
                                              \u8fd9\u4e9b\u64cd\u4f5c\u7528\u4e8e\u67e5\u627e\u6d41\u4e2d\u7684\u5143\u7d20\uff1a<\/p>\n\n\n\n
                                                \n
                                              • \u2022 findFirst\uff1a\u8fd4\u56de\u6d41\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20<\/li>\n\n\n\n
                                              • \u2022 findAny\uff1a\u8fd4\u56de\u6d41\u4e2d\u7684\u4efb\u610f\u4e00\u4e2a\u5143\u7d20\uff08\u5728\u5e76\u884c\u6d41\u4e2d\u7279\u522b\u6709\u7528\uff09<\/li>\n<\/ul>\n\n\n\n
                                                Optional<String> first = words.stream()\n    .findFirst();\n\nOptional<String> any = words.stream()\n    .findAny();<\/pre>\n\n\n\n
                                                \u3000<\/p>\n\n\n\n
                                                3. \u9ad8\u7ea7\u64cd\u4f5c<\/strong><\/p>\n\n\n\n
                                                  \n
                                                • 3.1 \u5206\u7ec4\u64cd\u4f5c\uff08groupingBy\uff09<\/li>\n<\/ul>\n\n\n\n
                                                  groupingBy \u64cd\u4f5c\u7528\u4e8e\u5c06\u6d41\u4e2d\u7684\u5143\u7d20\u6309\u7167\u6307\u5b9a\u7684\u6761\u4ef6\u8fdb\u884c\u5206\u7ec4\uff0c\u8fd4\u56de\u4e00\u4e2a Map\u3002<\/p>\n\n\n\n
                                                  \/\/ \u6309\u90e8\u95e8\u5206\u7ec4\nMap<String, List<Employee>> deptGroups = employees.stream()\n    .collect(Collectors.groupingBy(Employee::getDepartment));\n\n\/\/ \u6309\u90e8\u95e8\u5206\u7ec4\u5e76\u7edf\u8ba1\u6bcf\u4e2a\u90e8\u95e8\u7684\u5458\u5de5\u6570\u91cf\nMap<String, Long> deptCount = employees.stream()\n    .collect(Collectors.groupingBy(\n        Employee::getDepartment,\n        Collectors.counting()\n    ));\n\n\/\/ \u6309\u90e8\u95e8\u5206\u7ec4\u5e76\u8ba1\u7b97\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\nMap<String, Double> deptAvgSalary = employees.stream()\n    .collect(Collectors.groupingBy(\n        Employee::getDepartment,\n        Collectors.averagingDouble(Employee::getSalary)\n    ));\n\n\/\/ \u591a\u7ea7\u5206\u7ec4\uff1a\u5148\u6309\u90e8\u95e8\u5206\u7ec4\uff0c\u518d\u6309\u804c\u4f4d\u5206\u7ec4\nMap<String, Map<String, List<Employee>>> deptAndPositionGroups = employees.stream()\n    .collect(Collectors.groupingBy(\n        Employee::getDepartment,\n        Collectors.groupingBy(Employee::getPosition)\n    ));<\/pre>\n\n\n\n
                                                  \u3000<\/p>\n\n\n\n
                                                    \n
                                                  • 3.2 \u5206\u533a\u64cd\u4f5c\uff08partitioningBy\uff09<\/li>\n<\/ul>\n\n\n\n
                                                    partitioningBy \u64cd\u4f5c\u7528\u4e8e\u5c06\u6d41\u4e2d\u7684\u5143\u7d20\u6309\u7167\u6307\u5b9a\u7684\u6761\u4ef6\u5206\u4e3a\u4e24\u7ec4\uff0c\u8fd4\u56de\u4e00\u4e2a Map<Boolean, List>\u3002<\/p>\n\n\n\n
                                                    \/\/ \u5c06\u5458\u5de5\u5206\u4e3a\u9ad8\u85aa\u548c\u4f4e\u85aa\u4e24\u7ec4\uff08\u4ee510000\u4e3a\u754c\u9650\uff09\nMap<Boolean, List<Employee>> salaryGroups = employees.stream()\n    .collect(Collectors.partitioningBy(e -> e.getSalary() > 10000));\n\n\/\/ \u5206\u533a\u5e76\u7edf\u8ba1\u6570\u91cf\nMap<Boolean, Long> salaryCount = employees.stream()\n    .collect(Collectors.partitioningBy(\n        e -> e.getSalary() > 10000,\n        Collectors.counting()\n    ));<\/pre>\n\n\n\n
                                                    \u3000<\/p>\n\n\n\n
                                                      \n
                                                    • 3.3 \u7edf\u8ba1\u64cd\u4f5c<\/li>\n<\/ul>\n\n\n\n
                                                      Stream \u63d0\u4f9b\u4e86\u4e30\u5bcc\u7684\u7edf\u8ba1\u64cd\u4f5c\uff0c\u53ef\u4ee5\u65b9\u4fbf\u5730\u8fdb\u884c\u6570\u503c\u8ba1\u7b97\u3002<\/p>\n\n\n\n
                                                      \/\/ \u8ba1\u7b97\u5de5\u8d44\u7684\u7edf\u8ba1\u4fe1\u606f\nDoubleSummaryStatisticssalaryStats= employees.stream()\n    .collect(Collectors.summarizingDouble(Employee::getSalary));\n\n\/\/ \u83b7\u53d6\u7edf\u8ba1\u7ed3\u679c\ndoubleavgSalary= salaryStats.getAverage();\ndoublemaxSalary= salaryStats.getMax();\ndoubleminSalary= salaryStats.getMin();\ndoubletotalSalary= salaryStats.getSum();\nlongcount= salaryStats.getCount();<\/pre>\n\n\n\n
                                                      \u3000<\/p>\n\n\n\n
                                                        \n
                                                      • 3.4 \u8fde\u63a5\u64cd\u4f5c\uff08joining\uff09<\/li>\n<\/ul>\n\n\n\n
                                                        joining \u64cd\u4f5c\u7528\u4e8e\u5c06\u6d41\u4e2d\u7684\u5143\u7d20\u8fde\u63a5\u6210\u5b57\u7b26\u4e32\u3002<\/p>\n\n\n\n
                                                        \/\/ \u5c06\u6240\u6709\u5458\u5de5\u540d\u5b57\u7528\u9017\u53f7\u8fde\u63a5\nString allNames = employees.stream()\n    .map(Employee::getName)\n    .collect(Collectors.joining(\", \"));\n\n\/\/ \u4f7f\u7528\u524d\u7f00\u548c\u540e\u7f00\nString namesWithBrackets = employees.stream()\n    .map(Employee::getName)\n    .collect(Collectors.joining(\", \", \"[\", \"]\"));<\/pre>\n\n\n\n
                                                        \u3000<\/p>\n\n\n\n
                                                          \n
                                                        • 3.5 \u81ea\u5b9a\u4e49\u6536\u96c6\u5668<\/li>\n<\/ul>\n\n\n\n
                                                          \u9664\u4e86\u4f7f\u7528\u5185\u7f6e\u7684\u6536\u96c6\u5668\uff0c\u6211\u4eec\u8fd8\u53ef\u4ee5\u81ea\u5b9a\u4e49\u6536\u96c6\u5668\u3002<\/p>\n\n\n\n
                                                          \/\/ \u81ea\u5b9a\u4e49\u6536\u96c6\u5668\uff1a\u6536\u96c6\u6240\u6709\u5458\u5de5\u7684\u5de5\u8d44\u5230List\nList<Double> salaries = employees.stream()\n    .collect(Collectors.collectingAndThen(\n        Collectors.mapping(\n            Employee::getSalary,\n            Collectors.toList()\n        ),\n        Collections::unmodifiableList\n    ));<\/pre>\n\n\n\n
                                                          \u3000<\/p>\n\n\n\n
                                                            \n
                                                          • 3.6 \u6d41\u8f6c\u6362\u64cd\u4f5c<\/li>\n<\/ul>\n\n\n\n
                                                            Stream \u63d0\u4f9b\u4e86\u591a\u79cd\u6d41\u8f6c\u6362\u64cd\u4f5c\uff0c\u53ef\u4ee5\u5904\u7406\u4e0d\u540c\u7c7b\u578b\u7684\u6d41\u3002<\/p>\n\n\n\n
                                                            \/\/ \u8f6c\u6362\u4e3aIntStream\nIntStreamintStream= employees.stream()\n    .mapToInt(Employee::getAge);\n\n\/\/ \u8f6c\u6362\u4e3aDoubleStream\nDoubleStreamdoubleStream= employees.stream()\n    .mapToDouble(Employee::getSalary);\n\n\/\/ \u8f6c\u6362\u4e3aLongStream\nLongStreamlongStream= employees.stream()\n    .mapToLong(Employee::getId);<\/pre>\n\n\n\n
                                                             \u3000<\/p>\n\n\n\n
                                                              \n
                                                            • 3.7 \u6d41\u5408\u5e76\u64cd\u4f5c<\/li>\n<\/ul>\n\n\n\n
                                                              Stream \u63d0\u4f9b\u4e86\u5408\u5e76\u591a\u4e2a\u6d41\u7684\u64cd\u4f5c\u3002<\/p>\n\n\n\n
                                                              \/\/ \u5408\u5e76\u4e24\u4e2a\u6d41\nStream<String> stream1 = Stream.of(\"A\", \"B\", \"C\");\nStream<String> stream2 = Stream.of(\"D\", \"E\", \"F\");\nStream<String> combined = Stream.concat(stream1, stream2);\n\n\/\/ \u4f7f\u7528flatMap\u5408\u5e76\u591a\u4e2a\u6d41\nList<List<String>> lists = Arrays.asList(\n    Arrays.asList(\"A\", \"B\"),\n    Arrays.asList(\"C\", \"D\"),\n    Arrays.asList(\"E\", \"F\")\n);\nList<String> flattened = lists.stream()\n    .flatMap(List::stream)\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                                                              \u3000<\/p>\n\n\n\n
                                                                \n
                                                              • 3.8 \u6d41\u9650\u5236\u548c\u8df3\u8fc7\u64cd\u4f5c<\/li>\n<\/ul>\n\n\n\n
                                                                Stream \u63d0\u4f9b\u4e86\u9650\u5236\u548c\u8df3\u8fc7\u5143\u7d20\u7684\u64cd\u4f5c\u3002<\/p>\n\n\n\n
                                                                \/\/ \u9650\u5236\u6d41\u4e2d\u7684\u5143\u7d20\u6570\u91cf\nList<Employee> firstFive = employees.stream()\n    .limit(5)\n    .collect(Collectors.toList());\n\n\/\/ \u8df3\u8fc7\u524dN\u4e2a\u5143\u7d20\nList<Employee> skipFirstFive = employees.stream()\n    .skip(5)\n    .collect(Collectors.toList());\n\n\/\/ \u5206\u9875\u64cd\u4f5c\nintpageSize=10;\nintpageNumber=2;\nList<Employee> page = employees.stream()\n    .skip((pageNumber - 1) * pageSize)\n    .limit(pageSize)\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                                                                \u3000<\/p>\n\n\n\n
                                                                \u56db\u3001Stream \u6d41\u7684\u5e76\u884c\u5904\u7406<\/strong><\/p>\n\n\n\n
                                                                \n\n\n\n
                                                                1. \u5e76\u884c\u6d41\u521b\u5efa<\/p>\n\n\n\n
                                                                \u5e76\u884c\u6d41\u53ef\u4ee5\u5145\u5206\u5229\u7528\u591a\u6838\u5904\u7406\u5668\u7684\u4f18\u52bf\uff0c\u63d0\u9ad8\u5904\u7406\u5927\u91cf\u6570\u636e\u65f6\u7684\u6027\u80fd\u3002\u4f7f\u7528 parallelStream() \u65b9\u6cd5\u53ef\u4ee5\u521b\u5efa\u5e76\u884c\u6d41\u3002<\/p>\n\n\n\n
                                                                List<String> result = words.parallelStream()\n    .filter(word -> word.length() > 5)\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                                                                \u3000<\/p>\n\n\n\n
                                                                2. \u6027\u80fd\u8003\u8651<\/p>\n\n\n\n
                                                                \u5728\u4f7f\u7528\u5e76\u884c\u6d41\u65f6\uff0c\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n\n\n\n
                                                                  \n
                                                                • \u2022 \u6570\u636e\u91cf\u8981\u8db3\u591f\u5927\uff0c\u624d\u80fd\u4f53\u73b0\u5e76\u884c\u5904\u7406\u7684\u4f18\u52bf<\/li>\n\n\n\n
                                                                • \u2022 \u64cd\u4f5c\u5e94\u8be5\u662f\u65e0\u72b6\u6001\u7684\uff0c\u907f\u514d\u5171\u4eab\u53ef\u53d8\u72b6\u6001<\/li>\n\n\n\n
                                                                • \u2022 \u64cd\u4f5c\u5e94\u8be5\u662f\u53ef\u5e76\u884c\u7684\uff0c\u907f\u514d\u987a\u5e8f\u4f9d\u8d56<\/li>\n\n\n\n
                                                                • \u2022 \u8003\u8651\u7ebf\u7a0b\u5b89\u5168\u7684\u95ee\u9898<\/li>\n<\/ul>\n\n\n\n
                                                                  \/\/ \u9002\u5408\u5e76\u884c\u5904\u7406\u7684\u573a\u666f\nList<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);\nint sum = numbers.parallelStream()\n    .mapToInt(Integer::intValue)\n    .sum();<\/pre>\n\n\n\n
                                                                  \u3000<\/p>\n\n\n\n
                                                                  \u4e94\u3001\u5b9e\u9645\u5e94\u7528\u573a\u666f<\/strong><\/p>\n\n\n\n
                                                                  \n\n\n\n
                                                                  1. \u6570\u636e\u7edf\u8ba1<\/p>\n\n\n\n
                                                                  \/\/ \u8ba1\u7b97\u5e73\u5747\u5e74\u9f84\ndouble avgAge = employees.stream()\n    .mapToInt(Employee::getAge)\n    .average()\n    .orElse(0.0);\n\n\/\/ \u6309\u90e8\u95e8\u5206\u7ec4\u7edf\u8ba1\nMap<String, Long> deptCount = employees.stream()\n    .collect(Collectors.groupingBy(\n        Employee::getDepartment,\n        Collectors.counting()\n    ));<\/pre>\n\n\n\n
                                                                  \u3000<\/p>\n\n\n\n
                                                                  2. \u6570\u636e\u8f6c\u6362<\/p>\n\n\n\n
                                                                  \/\/ \u5bf9\u8c61\u8f6c\u6362\nList<EmployeeDTO> dtos = employees.stream()\n    .map(employee -> new EmployeeDTO(\n        employee.getId(),\n        employee.getName(),\n        employee.getSalary()\n    ))\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                                                                  \u3000<\/p>\n\n\n\n
                                                                  3. \u6570\u636e\u8fc7\u6ee4\u548c\u805a\u5408<\/p>\n\n\n\n
                                                                  \/\/ \u627e\u51fa\u9ad8\u85aa\u5458\u5de5\nList<Employee> highPaid = employees.stream()\n    .filter(e -> e.getSalary() > 10000)\n    .sorted(Comparator.comparing(Employee::getSalary).reversed())\n    .collect(Collectors.toList());<\/pre>\n\n\n\n
                                                                  \u3000<\/p>\n\n\n\n
                                                                  4. \u590d\u6742\u6570\u636e\u5904\u7406<\/p>\n\n\n\n
                                                                  \/\/ \u6309\u90e8\u95e8\u5206\u7ec4\uff0c\u8ba1\u7b97\u6bcf\u4e2a\u90e8\u95e8\u7684\u5de5\u8d44\u7edf\u8ba1\u4fe1\u606f\nMap<String, DoubleSummaryStatistics> deptSalaryStats = employees.stream()\n    .collect(Collectors.groupingBy(\n        Employee::getDepartment,\n        Collectors.summarizingDouble(Employee::getSalary)\n    ));\n\n\/\/ \u627e\u51fa\u6bcf\u4e2a\u90e8\u95e8\u5de5\u8d44\u6700\u9ad8\u7684\u5458\u5de5\nMap<String, Optional<Employee>> deptHighestPaid = employees.stream()\n    .collect(Collectors.groupingBy(\n        Employee::getDepartment,\n        Collectors.maxBy(Comparator.comparing(Employee::getSalary))\n    ));\n\n\/\/ \u6309\u5de5\u8d44\u8303\u56f4\u5206\u7ec4\u7edf\u8ba1\nMap<String, Long> salaryRangeCount = employees.stream()\n    .collect(Collectors.groupingBy(\n        e -> {\n            doublesalary= e.getSalary();\n            if (salary < 5000) return\"\u4f4e\u85aa\";\n            if (salary < 10000) return\"\u4e2d\u85aa\";\n            return\"\u9ad8\u85aa\";\n        },\n        Collectors.counting()\n    ));<\/pre>\n\n\n\n
                                                                  \u3000<\/p>\n\n\n\n
                                                                  \u516d\u3001Stream \u6d41\u7684\u6700\u4f73\u5b9e\u8df5<\/strong><\/p>\n\n\n\n
                                                                  \n\n\n\n
                                                                    \n
                                                                  1. 1. \u4fdd\u6301\u94fe\u5f0f\u8c03\u7528\u7684\u53ef\u8bfb\u6027<\/li>\n\n\n\n
                                                                  2. 2. \u5408\u7406\u4f7f\u7528\u5e76\u884c\u6d41<\/li>\n\n\n\n
                                                                  3. 3. \u6ce8\u610f\u4e2d\u95f4\u64cd\u4f5c\u548c\u7ec8\u7aef\u64cd\u4f5c\u7684\u533a\u522b<\/li>\n\n\n\n
                                                                  4. 4. \u9002\u5f53\u4f7f\u7528 Optional \u5904\u7406\u7a7a\u503c<\/li>\n\n\n\n
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