如何将对象转换为java中的int? [英] How to cast an Object to an int in java?
问题描述
如何在Java中将对象转换为int?
How can I cast an Object to an int in java?
推荐答案
如果您确定此对象是 Integer
:
int i = (Integer) object;
或者,从Java 7开始,你可以写成:
Or, starting from Java 7, you can equivalently write:
int i = (int) object;
注意,它可以抛出 ClassCastException
如果您的对象不是 Integer
和 如果你的对象是
null
。
Beware, it can throw a ClassCastException
if your object isn't an Integer
and a NullPointerException
if your object is null
.
这样你就可以假设NullPointerException 你的对象是一个整数(包装的int),你unbox它成一个int。
This way you assume that your Object is an Integer (the wrapped int) and you unbox it into an int.
int
原语,所以它不能存储为对象
,唯一的办法是有一个 int
考虑/ 整数
然后存储为对象
。
int
is a primitive so it can't be stored as an Object
, the only way is to have an int
considered/boxed as an Integer
then stored as an Object
.
如果你的对象是 String
,那么你可以使用 Integer.valueOf()
方法将其转换为一个简单的int:
If your object is a String
, then you can use the Integer.valueOf()
method to convert it into a simple int :
int i = Integer.valueOf((String) object);
它可以抛出 NumberFormatException
如果您的对象不是真的 String
以整数作为内容。
It can throw a NumberFormatException
if your object isn't really a String
with an integer as content.
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Resources :
- Oracle.com - Autoboxing
- Oracle.com - Primitive Data types
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