Java中的参考究竟是什么？ [英] What exactly is a reference in Java?

问题描述

Java中的参考究竟是什么？它是一个内存地址吗？ Java引用是否相当于解除引用的C ++指针？

What exactly is a reference in Java? Is it a memory address? Is a Java reference the equivalent of a dereferenced C++ pointer?

换句话说，给出以下内容：

In other words, given the following:

Object o1 = new Object();
Object o2 = new Object();

o1 == o2

以上比较是否相当于比较两个C ++中的指针？

Is the above comparison the equivalent of comparing two pointers in C++?

推荐答案

o1 == o2 几乎相同比较C / C ++中的两个指针，是的。

o1 == o2 is pretty much equivalent to comparing two pointers in C/C++, yes.

但是Java中的引用和C / C ++中的指针之间存在两个主要区别：

But there are a two main differences between references in Java and pointers in C/C++ that are quite important:

• Java引用不能做指针运算：你不能添加3到引用，你只能 让它指向另一个（已知的）对象


• 强烈输入Java引用：你不能重新解释引用另一端的内容，除非你将它重新解释为该对象实际上是的类型。

• Java references can't do pointer arithmetic: you can't "add 3" to a reference, you can only let it point to another (known) object
• Java references are stongly typed: you can't "reinterpret" what lies on the other end of a reference unless you reinterpret it as a type that that object actually is.

这也是关于这个词的简短说明引用：C ++的引用与C中的指针和Java中的引用完全不同（但我对C ++的了解并不足以告诉您指定的内容） ics）。

Also a short note about the word "reference": C++ has references that act quite differently from both pointers in C and references in Java (but I don't know enough about C++ to tell you the specifics).

有关此问题的详细讨论，请参阅关于programmers.SE的这个相关问题。

For a thorough discussion of this, see this related question on programmers.SE.

这篇关于Java中的参考究竟是什么？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！