为什么 Stream 没有 toList() 方法? [英] Why didn't Stream have a toList() method?

问题描述

在使用 Java 8 流时，很常见的做法是获取一个列表，从中创建一个流，然后进行业务并将其转换回来.类似的东西:

When using the Java 8 streams, it's quite common to take a list, create a stream from it, do the business and convert it back. Something like:

 Stream.of(-2,1,2,-5)
        .filter(n -> n > 0)
        .map(n -> n * n)
        .collect(Collectors.toList());

为什么.collect(Collectors.toList())"部分没有捷径/方便的方法?在Stream接口上，有一种将结果转换为数组的方法叫做toArray()，为什么缺少toList()?

Why there is no short-cut/convenient method for the '.collect(Collectors.toList())' part? On Stream interface, there is method for converting the results to array called toArray(), why the toList() is missing?

恕我直言，将结果转换为列表比转换为数组更常见.我可以忍受，但称之为丑陋很烦人.

IMHO, converting the result to list is more common than to array. I can live with that, but it is quite annoying to call this ugliness.

有什么想法吗?

推荐答案

最近我写了一个名为 StreamEx 的小型库，它扩展了 Java流并在许多其他功能中提供这种确切的方法:

Recently I wrote a small library called StreamEx which extends Java streams and provides this exact method among many other features:

StreamEx.of(-2,1,2,-5)
    .filter(n -> n > 0)
    .map(n -> n * n)
    .toList();

还有 toSet()、toCollection(Supplier)、joining()、groupingBy() 等快捷方法.

Also toSet(), toCollection(Supplier), joining(), groupingBy() and other shortcut methods are available there.

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