How to convert an Optionallt;Tgt; into a Streamlt;Tgt;?(如何转换可选的lt;Tgt;进入 Stream lt;Tgt;?)

本文介绍了如何转换可选的<T>进入 Stream <T>?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

I want to prepend a stream with an Optional. Since Stream.concat can only concatinate Streams I have this question:

How do I convert an Optional<T> into a Stream<T>?

Example:

Optional<String> optional = Optional.of("Hello");
Stream<String> texts = optional.stream(); // not working

解决方案

In Java-9 the missing stream() method is added, so this code works:

Stream<String> texts = optional.stream();

See JDK-8050820. Download Java-9 here.

这篇关于如何转换可选的&lt;T&gt;进入 Stream &lt;T&gt;?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！