如何从Java方法返回多个对象？ [英] How to return multiple objects from a Java method?

问题描述

我想从Java方法返回两个对象，并想知道这样做的好方法是什么？

I want to return two objects from a Java method and was wondering what could be a good way of doing so?

我能想到的可能方法是：返回 HashMap （因为这两个对象是相关的）或返回对象的 ArrayList / code> objects。

The possible ways I can think of are: return a HashMap (since the two Objects are related) or return an ArrayList of Object objects.

更准确地说，我要返回的两个对象是（a） List 的对象和（b）逗号分隔的名称。

To be more precise, the two objects I want to return are (a) List of objects and (b) comma separated names of the same.

我想从一个方法返回这两个对象，因为我不想遍历列表获取逗号分隔名称的对象（我可以在此方法的同一循环中执行此操作）。

I want to return these two Objects from one method because I dont want to iterate through the list of objects to get the comma separated names (which I can do in the same loop in this method).

不知何故，返回 HashMap 看起来并不是一种非常优雅的方式。

Somehow, returning a HashMap does not look a very elegant way of doing so.

推荐答案

如果你想要返回两个对象想要返回一个封装两个对象的单个对象。

If you want to return two objects you usually want to return a single object that encapsulates the two objects instead.

你可以返回一个 ListdObject的List / code>这样的对象：

You could return a List of NamedObject objects like this:

public class NamedObject<T> {
  public final String name;
  public final T object;

  public NamedObject(String name, T object) {
    this.name = name;
    this.object = object;
  }
}

然后你可以轻松返回 List< NamedObject< WhateverTypeYouWant>> 。

另外：为什么要返回以逗号分隔的名称列表而不是列表与LT;字符串> ？或者更好的是，返回 Map< String，TheObjectType> ，其中键是对象的名称和值（除非您的对象具有指定的顺序，在这种情况下为 NavigableMap 可能就是你想要的。

Also: Why would you want to return a comma-separated list of names instead of a List<String>? Or better yet, return a Map<String,TheObjectType> with the keys being the names and the values the objects (unless your objects have specified order, in which case a NavigableMap might be what you want.

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