Java 把迭代器转换为流

给定一个Iterator，任务是在Java中把它转换成Stream。

例子。

输入: Iterator = {1, 2, 3, 4, 5}
输出: {1, 2, 3, 4, 5}

输入: Iterator = {‘G’, ‘e’, ‘e’, ‘k’, ‘s’}
输出: {‘G’, ‘e’, ‘e’, ‘k’, ‘s’}

办法。

1. 获取迭代器。
2. 使用Spliterators.spliteratorUnknownSize()方法将迭代器转换为Spliterator。
3. 使用StreamSupport.stream()方法将形成的Spliterator转换成顺序流。
4. 返回流。

下面是上述方法的实现。

// Java program to get a Stream
// from a given Iterator
  
import java.util.*;
import java.util.stream.*;
  
class GFG {
  
    // Function to get the Stream
    public static <T> Stream<T>
    getStreamFromIterator(Iterator<T> iterator)
    {
  
        // Convert the iterator to Spliterator
        Spliterator<T>
            spliterator = Spliterators
                              .spliteratorUnknownSize(iterator, 0);
  
        // Get a Sequential Stream from spliterator
        return StreamSupport.stream(spliterator, false);
    }
  
    // Driver code
    public static void main(String[] args)
    {
  
        // Get the Iterator
        Iterator<Integer>
            iterator = Arrays.asList(1, 2, 3, 4, 5)
                           .iterator();
  
        // Get the Stream from the Iterator
        Stream<Integer>
            stream = getStreamFromIterator(iterator);
  
        // Print the elements of stream
        stream.forEach(s -> System.out.println(s));
    }
}

输出:

1
2
3
4
5