错误:通用数组创建 [英] Error: Generic Array Creation

问题描述

我不明白通用数组创建的错误.
首先，我尝试了以下操作:

I don't understand the error of Generic Array Creation.
First I tried the following:

  public PCB[] getAll() {
       PCB[] res = new PCB[list.size()];
           for (int i = 0; i < res.length; i++) {
               res[i] = list.get(i);
            }
       list.clear();
       return res;
}

然后我尝试这样做:

Then I tried doing this:

PCB[] res = new PCB[100];

我一定错过了一些看起来正确的原因.我试着查了一下，我真的查到了.什么都没有点击.

I must be missing something cause that seems right. I tried looking it up I really did. And nothing is clicking.

我的问题是:我能做些什么来解决这个问题?

My question is: What can I do to fix this?

错误是:

the error is :

.\Queue.java:26: generic array creation
PCB[] res = new PCB[200];
            ^
Note: U:\Senior Year\CS451- file      
uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error

工具完成，退出代码 1

Tool completed with exit code 1

推荐答案

您不能创建具有通用组件类型的数组.

You can't create arrays with a generic component type.

改为创建一个显式类型的数组，例如 Object[].如果需要，您可以将其转换为 PCB[]，但在大多数情况下我不建议这样做.

Create an array of an explicit type, like Object[], instead. You can then cast this to PCB[] if you want, but I don't recommend it in most cases.

PCB[] res = (PCB[]) new Object[list.size()]; /* Not type-safe. */

如果您想要类型安全，请使用 java.util.List 之类的集合而不是数组.

If you want type safety, use a collection like java.util.List<PCB> instead of an array.

顺便说一下，如果 list 已经是 java.util.List，你应该使用它的 toArray() 方法之一，而不是在您的代码中复制它们.但这并不能解决您的类型安全问题.

By the way, if list is already a java.util.List, you should use one of its toArray() methods, instead of duplicating them in your code. This doesn't get your around the type-safety problem though.

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