compareTo()与equals() [英] compareTo() vs. equals()

问题描述

在Java中测试String的相等性时，我一直使用equals()，因为对我来说这似乎是最自然的方法.毕竟，它的名字已经说明了它打算做什么.但是，我的一位同事最近告诉我，我被教导要使用compareTo() == 0代替equals().这感觉很不自然(因为compareTo()是为了提供顺序而不是为了比较而进行比较)，甚至有些危险(因为compareTo() == 0不一定在所有情况下都意味着平等，即使我知道它对String而言也是如此) )给我.

When testing for equality of String's in Java I have always used equals() because to me this seems to be the most natural method for it. After all, its name already says what it is intended to do. However, a colleague of mine recently told me had been taught to use compareTo() == 0 instead of equals(). This feels unnatural (as compareTo() is meant to provide an ordering and not compare for equality) and even somewhat dangerous (because compareTo() == 0 does not necessarily imply equality in all cases, even though I know it does for String's) to me.

他不知道为什么要教他用compareTo()代替equals()来使用String，而且我也找不到任何原因.这真的是个人喜好问题，还是使用这两种方法的真正原因?

He did not know why he was taught to use compareTo() instead of equals() for String's, and I could also not find any reason why. Is this really a matter of personal taste, or is there any real reason for either method?

推荐答案

一个区别是"foo".equals((String)null)返回false，而"foo".compareTo((String)null) == 0抛出NullPointerException.因此，即使对于字符串，它们也不总是可以互换的.

A difference is that "foo".equals((String)null) returns false while "foo".compareTo((String)null) == 0 throws a NullPointerException. So they are not always interchangeable even for Strings.

这篇关于compareTo()与equals()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！