Java中的双倍与双倍 [英] Double vs double in java

问题描述

可能的重复:
Java:比较不同的 double 和 Double

在我的一个实验室的示例 Java 程序中，我有两种不同的方法，分别采用 Double 和 double 参数.
在向它们传递参数时如何区分它们?

In a sample java program for one of my labs, I have two different methods taking Double and double parameters respectively.
How do I differentiate between them when passing arguments to them?

推荐答案

首先，您需要了解这两种类型之间的区别.double 是原始类型，而 Double 是对象.

First off you need to understand the difference between the two types. double is a primitive type whereas Double is an Object.

下面的代码显示了一个重载方法，我认为它与您的实验室代码相似.

The code below shows an overloaded method, which I assume is similar to your lab code.

void doStuff(Double d){ System.out.println("Object call"); }
void doStuff(double d){ System.out.println("Primitive call"); }

您可以通过多种方式调用这些方法:

There are several ways you can call these methods:

doStuff(100);
doStuff(200d);
doStuff(new Double(100));

这些调用将导致:

"Primitive call"
"Primitive call"
"Object call"

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