如何在 Java 中将 Object 类型转换为 int 类型？

Question

I'm looking for a way to convert a Object type (as in the wildcard type which can store many different types) to an int type. In all of my searching I have not found an answer to this question on the site.

I have a Object[] array which stores only integers and I need to perform some math using one of the integers. For example int result = array[3] + 2; . This arithmetic won't work unless I can cast/convert that Object to an int .

Answer 1

The others that say Integer[] and int[] are the solutions to the question is very true when only numbers will be added in the array. But, In some cases, there are requirements that we should follow. So Object that contains number can be casted to Integer and unbox it to int is more likely what the OP needs.

Answer 2

如果你自己定义对象数组，我想你可以使用int数组，如果其他方法返回这个数据类型，你可以转换为int，但你需要检查对象数组元素是否不是

Answer 3

I have a Object[] array which stores only integers

Solution: don't. Use Integer[] , or better still int[] , as @dave has already told you.

The suggestion to cast the objects twice is inefficient and error-prone.

Don't cause downstream problems for yourself by weak typing.

As a side benefit, if your assertion that it stores only integers turns out to be untrue, you will now find out at compile time, instead of at runtime.