Java 中的 ArrayList 是什么意思 [英] what is this mean in the ArrayList in Java

问题描述

我是 Java 新手，见过这样的 ArrayList 示例.

 listing = new ArrayList();

我知道如果我想创建一个空数组列表.然后我将使用 ArrayList()

但我不明白ArrayList"和()"之间的是什么.>

谁能给我解释一下?

谢谢

解决方案

这是 Java 泛型. 表示 ArrayList 将只包含 Lot 类型的对象.这很有用，因为编译器可以对您的 ArrayList 进行类型检查.

I'm new in Java, and I have seen a ArrayList example like this.

  listing = new ArrayList<Lot>();

I know that if I want to create an empty array list. Then I will use ArrayList()

But I don't understand what is the <Lot> between the "ArrayList" and "()".

Can someone explain it to me?

Thanks

解决方案

This is Java Generics. The <Lot> indicates that the ArrayList will contain only objects of type Lot. It is useful because the compiler can do type checking on your ArrayList.

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