java - 如何将Java 8 Stream转换为数组？(How to convert a Java 8 Stream to an Array?)

Question

将Java 8 Stream转换为数组的最简单/最快捷的方法是什么？

  ask by translate from so

Answer 1

The easiest method is to use the toArray(IntFunction<A[]> generator) method with an array constructor reference.

(最简单的方法是将toArray(IntFunction<A[]> generator)方法与数组构造函数引用一起使用。)

This is suggested in the API documentation for the method .

(在API文档中建议该方法 。)

String[] stringArray = stringStream.toArray(String[]::new);

What it does is find a method that takes in an integer (the size) as argument, and returns a String[] , which is exactly what (one of the overloads of) new String[] does.

(它的作用是找到一个以整数（大小）作为参数的方法，并返回String[] ，而这正是new String[] （的重载之一）所做的事情。)

You could also write your own IntFunction :

(您也可以编写自己的IntFunction ：)

Stream<String> stringStream = ...;
String[] stringArray = stringStream.toArray(size -> new String[size]);

The purpose of the IntFunction<A[]> generator is to convert an integer, the size of the array, to a new array.

(IntFunction<A[]> generator是将整数（数组的大小）转换为新数组。)

Example code:

(示例代码：)

Stream<String> stringStream = Stream.of("a", "b", "c");
String[] stringArray = stringStream.toArray(size -> new String[size]);
Arrays.stream(stringArray).forEach(System.out::println);

Prints:

(打印：)

a
b
c