C＃lambda在java 8中选择 [英] C# lambda select in java 8

问题描述

假设我在C＃中有一个对象：

Say I have an object in C#:

public class Person
{
    public string Name{get;set;}
    public int Age{get;set;}
}

要在C＃中从此列表中选择名称，我将执行以下操作：

To select the names from this list in C# I would do the following:

List<string> names = person.Select(x=>x.Name).ToList();

我如何在Java 8中做同样的事情？

How would I do the same thing in Java 8?

推荐答案

如果您有列表< Person>等人员列表人; 你可以说

List<String> names
  =persons.stream().map(x->x.getName()).collect(Collectors.toList());

或者

List<String> names
  =persons.stream().map(Person::getName).collect(Collectors.toList());

但收集到列表或其他 Collection 仅用于需要 Collection 的旧版API。否则，您将继续使用流的操作，因为您可以使用集合执行所有操作，而不需要 String s，例如

But collecting into a List or other Collection is intented to be used with legacy APIs only where you need such a Collection. Otherwise you would proceed using the stream’s operations as you can do everything you could do with a Collection and a lot more without the need for an intermediate storage of the Strings, e.g.

persons.stream().map(Person::getName).forEach(System.out::println);

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