java中Stream的使用流程及注意

public class StreamAPITest1 {

    //创建 Stream方式一：通过集合

    @Test

    public void test1() {

        List<Employee> employees = EmployeeData.getEmployees();

        //efault Stream<E> stream() : 返回一个顺序流

        Stream<Employee> stream = employees.stream();

        //default Stream<E> parallelStream() : 返回一个并行流

        Stream<Employee> employeeStream = employees.parallelStream();

    }

    //创建 Stream方式二：通过数组

    @Test

    public void test2() {

        int[] arrs = {1, 2, 3, 6, 2};

        //调用Arrays类的static <T> Stream<T> stream(T[] array): 返回一个流

        IntStream stream = Arrays.stream(arrs);

        Employee e1 = new Employee(1001, "Tom");

        Employee e2 = new Employee(1002, "Jerry");

        Employee[] employees = {e1, e2};

        Stream<Employee> stream1 = Arrays.stream(employees);

    }

    //创建 Stream方式三：通过Stream的of()

    @Test

    public void test3() {

        Stream<Integer> integerStream = Stream.of(12, 34, 45, 65, 76);

    }

    //创建 Stream方式四：创建流

    @Test

    public void test4() {

        //迭代

        //public static<T> Stream<T> iterate(final T seed, final UnaryOperator<T> f)

        //遍历前10个偶数

        Stream.iterate(0, t -> t + 2).limit(10).forEach(System.out::println);

        //生成

        //public static<T> Stream<T> generate(Supplier<T> s)

        Stream.generate(Math::random).limit(10).forEach(System.out::println);

    }

}