List<String> nameStrs = Arrays.asList("Monkey", "Lion", "Giraffe","Lemur");
List<String> list = nameStrs.stream()
        .filter(s -> s.startsWith("L"))
        .map(String::toUpperCase)
        .sorted()
        .collect(toList());
System.out.println(list);

Stream.of("Monkey", "Lion", "Giraffe", "Lemur", "Lion")
        .parallel()
        .forEach(System.out::println);
Stream.of("Monkey", "Lion", "Giraffe", "Lemur", "Lion")
        .parallel()
        .forEachOrdered(System.out::println);

Set<String> collectToSet = Stream.of(
   "Monkey", "Lion", "Giraffe", "Lemur", "Lion"
) 
.collect(Collectors.toSet());
//最終collectToSet 中的元素是:[Monkey, Lion, Giraffe, Lemur]，注意Set會去重。

List<String> collectToList = Stream.of(
   "Monkey", "Lion", "Giraffe", "Lemur", "Lion"
).collect(Collectors.toList());

// 最終collectToList中的元素是: [Monkey, Lion, Giraffe, Lemur, Lion]

LinkedList<String> collectToCollection = Stream.of(
   "Monkey", "Lion", "Giraffe", "Lemur", "Lion"
).collect(Collectors.toCollection(LinkedList::new));
//最終collectToCollection中的元素是: [Monkey, Lion, Giraffe, Lemur, Lion]

String[] toArray = Stream.of(
   "Monkey", "Lion", "Giraffe", "Lemur", "Lion"
) .toArray(String[]::new);
//最終toArray字符串?dāng)?shù)組中的元素是: [Monkey, Lion, Giraffe, Lemur, Lion]

Map<String, Integer> toMap = Stream.of(
    "Monkey", "Lion", "Giraffe", "Lemur", "Lion"
)
.distinct()
.collect(Collectors.toMap(
       Function.identity(),   //元素輸入就是輸出，作為key
       s -> (int) s.chars().distinct().count()// 輸入元素的不同的字母個數(shù)，作為value
));
// 最終toMap的結(jié)果是: {Monkey=6, Lion=4, Lemur=5, Giraffe=6}   

Map<Character, List<String>> groupingByList =  Stream.of(
    "Monkey", "Lion", "Giraffe", "Lemur", "Lion"
)
.collect(Collectors.groupingBy(
       s -> s.charAt(0) ,  //根據(jù)元素首字母分組，相同的在一組
       // counting()        // 加上這一行代碼可以實現(xiàn)分組統(tǒng)計
));
// 最終groupingByList內(nèi)的元素: {G=[Giraffe], L=[Lion, Lemur, Lion], M=[Monkey]}
//如果加上counting() ，結(jié)果是:  {G=1, L=3, M=1}

boolean containsTwo = IntStream.of(1, 2, 3).anyMatch(i -> i == 2);
// 判斷管道中是否包含2，結(jié)果是: true
long nrOfAnimals = Stream.of(
    "Monkey", "Lion", "Giraffe", "Lemur"
).count();
// 管道中元素數(shù)據(jù)總計結(jié)果nrOfAnimals: 4
int sum = IntStream.of(1, 2, 3).sum();
// 管道中元素數(shù)據(jù)累加結(jié)果sum: 6
OptionalDouble average = IntStream.of(1, 2, 3).average();
//管道中元素數(shù)據(jù)平均值average: OptionalDouble[2.0]
int max = IntStream.of(1, 2, 3).max().orElse(0);
//管道中元素數(shù)據(jù)最大值max: 3
IntSummaryStatistics statistics = IntStream.of(1, 2, 3).summaryStatistics();
// 全面的統(tǒng)計結(jié)果statistics: IntSummaryStatistics{count=3, sum=6, min=1, average=2.000000, max=3}