如何在Java中初始化List＜String＞对象？

本文翻译自&＃xff1a;How to initialize List object in Java?

I can not initialize a List as in the following code: 我无法初始化List&＃xff0c;如下面的代码所示&＃xff1a;

List supplierNames &＃61; new List();
supplierNames.add("sup1");
supplierNames.add("sup2");
supplierNames.add("sup3");
System.out.println(supplierNames.get(1));


I face the following error: 我面临以下错误&＃xff1a;

Cannot instantiate the type List 无法实例化类型List

How can I instantiate List ? 如何实例化List &＃xff1f;

#1楼

参考&＃xff1a;https://stackoom.com/question/uCgE/如何在Java中初始化List-String-对象

#2楼

You will need to use ArrayList or such. 您将需要使用ArrayList等。

List is an interface. List是一个接口。

Use this: 用这个&＃xff1a;

import java.util.ArrayList;...List supplierNames &＃61; new ArrayList();


#3楼

List is an interface, and you can not initialize an interface. List是一个接口&＃xff0c;您无法初始化接口。 Instantiate an implementing class instead. 实际上实例化一个实现类。

Like: 喜欢&＃xff1a;

List abc &＃61; new ArrayList();
List xyz &＃61; new LinkedList();


#4楼

List is an Interface , you cannot instantiate an Interface, because interface is a convention, what methods should have your classes. List是一个接口 &＃xff0c;你不能实例化一个接口&＃xff0c;因为接口是一个约定&＃xff0c;你的类应该有哪些方法。 In order to instantiate, you need some realizations(implementations) of that interface. 为了实例化&＃xff0c;您需要该接口的一些实现&＃xff08;实现&＃xff09;。 Try the below code with very popular implementations of List interface: 使用非常流行的List接口实现尝试以下代码&＃xff1a;

List supplierNames &＃61; new ArrayList();


or 要么

List supplierNames &＃61; new LinkedList();


#5楼

Depending on what kind of List you want to use, something like 取决于您要使用的List类型&＃xff0c;类似于

List supplierNames &＃61; new ArrayList();


should get you going. 应该让你去。

List is the interface, ArrayList is one implementation of the List interface. List是接口&＃xff0c;ArrayList是List接口的一个实现。 More implementations that may better suit your needs can be found by reading the JavaDocs of the List interface . 通过阅读List接口的JavaDocs&＃xff0c;可以找到更适合您需求的更多实现。

#6楼

List is an Interface . 列表是一个接口。 You cant use List to initialize it. 你不能使用List来初始化它。

List supplierNames &＃61; new ArrayList();


These are the some of List impelemented classes, 这些是列中的一些实例化的类&＃xff0c;

ArrayList, LinkedList, Vector


You could use any of this as per your requirement. 您可以根据自己的要求使用其中任何一项。 These each classes have its own features. 这些每个类都有自己的功能。