02-jdk8 stream操作

痛定思痛。 2023-10-11 14:59 57阅读 0赞

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70 2][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70 3][]

/**
     * Stream的使用
     * @date 2020/11/15 21:36
     */
    public class Demo5 {
        public static void main(String[] args) {
            //1、Collection对象中stream()和parallelStream 方法
            ArrayList<String> arrayList=new ArrayList<>();
            arrayList.add("apple");
            arrayList.add("huawei");
            arrayList.add("xiaomi");
    
            Stream<String> stream = arrayList.stream();
    //        Stream<String> stream = arrayList.parallelStream();//多线程
    //        stream.forEach(e-> System.out.println(e));
            stream.forEach(System.out::println);
    
            System.out.println("-------------------------");
    
            //2、Arrays工具类的stream方法
            String[]arr={"aaa","bbb","ccc"};
            Stream<String> stream2= Arrays.stream(arr);
            stream2.forEach(System.out::println);
    
            System.out.println("-------------------------");
            //3、Stream接口中的of、iterate、generate方法
            Stream<Integer> integerStream = Stream.of(20, 30, 40, 60);
            integerStream.forEach(System.out::println);
            System.out.println("-------------------------");
            //迭代流
            Stream<Integer> iterate = Stream.iterate(0, x -> x + 2);
            iterate.limit(5).forEach(System.out::println);
            System.out.println("-------------------------");
    
            //生成流
            Stream<Integer> generate = Stream.generate(() -> new Random().nextInt(100));
            generate.limit(10).forEach(System.out::println);
            System.out.println("-------------------------");
    
            //4、IntStream、LongStream、DoubleStream 的of、range、rangeClosed
            IntStream intStream = IntStream.of(100, 200, 300);
            intStream.forEach(System.out::println);
    
            IntStream range = IntStream.range(0, 5);//非闭合的 0-4
            IntStream range2 = IntStream.rangeClosed(0, 5); //闭合的 0-5
            range.forEach(System.out::println);
    
        }
    }

输出结果为：

apple
    huawei
    xiaomi
    -------------------------
    aaa
    bbb
    ccc
    -------------------------
    20
    30
    40
    60
    -------------------------
    0
    2
    4
    6
    8
    -------------------------
    87
    3
    68
    55
    83
    71
    99
    92
    88
    96
    -------------------------
    100
    200
    300
    0
    1
    2
    3
    4

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20201115225222609.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/2020111522524026.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20201115225254573.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20201115225419665.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hhY2NwSjJFRQ==,size_16,color_FFFFFF,t_70