Java中的十个"单行代码编程"(One Liner)

// Range是半开区间
 int[] ia = range(1, 10).map(i -> i * 2).toArray();
 List<Integer> result = range(1, 10).map(i -> i * 2).boxed().collect(toList());

range(1, 1000).sum();
 range(1, 1000).reduce(0, Integer::sum);
 Stream.iterate(0, i -> i + 1).limit(1000).reduce(0, Integer::sum);
 IntStream.iterate(0, i -> i + 1).limit(1000).reduce(0, Integer::sum);

final List<String> keywords = Arrays.asList("brown", "fox", "dog", "pangram");
final String tweet = "The quick brown fox jumps over a lazy dog. #pangram http://www.rinkworks.com/words/pangrams.shtml";

keywords.stream().anyMatch(tweet::contains);
keywords.stream().reduce(false, (b, keyword) -> b || tweet.contains(keyword), (l, r) -> l || r);

try (BufferedReader reader = new BufferedReader(new FileReader("data.txt"))) {
   String fileText = reader.lines().reduce("", String::concat);
 }

 try (BufferedReader reader = new BufferedReader(new FileReader("data.txt"))) {
   List<String> fileLines = reader.lines().collect(toCollection(LinkedList<String>::new));
 }

 try (Stream<String> lines = Files.lines(new File("data.txt").toPath(), Charset.defaultCharset())) {
   List<String> fileLines = lines.collect(toCollection(LinkedList<String>::new));
 }

range(1, 5).boxed().map(i -> { out.print("Happy Birthday "); if (i == 3) return "dear NAME"; else return "to You"; }).forEach(out::println);

Map<String, List<Integer>> result = Stream.of(49, 58, 76, 82, 88, 90).collect(groupingBy(forPredicate(i -> i > 60, "passed", "failed")));

FeedType feed = JAXB.unmarshal(new URL("http://search.twitter.com/search.atom?&q=java8"), FeedType.class);
JAXB.marshal(feed, System.out);

int min = Stream.of(14, 35, -7, 46, 98).reduce(Integer::min).get();
 min = Stream.of(14, 35, -7, 46, 98).min(Integer::compare).get();
 min = Stream.of(14, 35, -7, 46, 98).mapToInt(Integer::new).min();

 int max = Stream.of(14, 35, -7, 46, 98).reduce(Integer::max).get();
 max = Stream.of(14, 35, -7, 46, 98).max(Integer::compare).get();
 max = Stream.of(14, 35, -7, 46, 98).mapToInt(Integer::new).max();

long result = dataList.parallelStream().mapToInt(line -> processItem(line)).sum();

List<Album> albums = Arrays.asList(unapologetic, tailgates, red);

//筛选出至少有一个track评级4分以上的专辑，并按照名称排序后打印出来。
albums.stream()
  .filter(a -> a.tracks.stream().anyMatch(t -> (t.rating >= 4)))
  .sorted(comparing(album -> album.name))
  .forEach(album -> System.out.println(album.name));

//合并所有专辑的track
List<Track> allTracks = albums.stream()
  .flatMap(album -> album.tracks.stream())
  .collect(toList());

//根据track的评分对所有track分组
Map<Integer, List<Track>> tracksByRating = allTracks.stream()
  .collect(groupingBy(Track::getRating));