kotlin int盒装标识 [英] kotlin int boxed identity

问题描述

在我们的文档中

请注意，数字装箱不会保留身份

Note that boxing of numbers does not preserve identity

但下一个示例给出不同的结果

but the next examples give different results

val number1 = 127
val b1 : Int? = number1
val b2 : Int? = number1
print(b1 === b2) // this prints true

val number2 = 128
val c1 : Int? = number2
val c2 : Int? = number2
print(c1 === c2) // this prints false

数字大于127的工作符合预期，但是当大于128（8位）时，为什么？

In numbers greater than 127 works as expected but not when is above 128 (8 bits), why?

推荐答案

本文解释了它：< a href =http://javapapers.com/java/java-integer-cache/ =noreferrer> http://javapapers.com/java/java-integer-cache/

基本思想是Java标准库对-128到127之间的值使用缓存，因此它们总是引用相同的Integer对象（通过标识）。

The basic idea is that the Java standard lib uses a cache for values between -128 and 127, therefore they always refer to the same Integer object (by identity).

这篇关于kotlin int盒装标识的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！