我有一个关于编码一个空检查标准的一个疑问。 我想知道的。

I have a doubt regarding coding standard of a null check. I want to know the difference between

if(a!=null)

和

if(null!=a)

哪一个更好，使用哪一个，为什么？

which one is better,which one to use and why?

推荐答案

两者都是在Java中一样，因为只有布尔EX pressions可能是内部的，如果这仅仅是一个编码风格通过编程器preference，其中大部分使用空！= A 。

Both are same in Java, as only boolean expressions can be inside an if. This is just a coding style preference by programmer and most of them use null != a.

在空！= A 是旧做法在如Java，C ++编程语言（称为尤达条件）。 因为它是有效的写若（a = NULL）时，不慎分配空到一个所以写空首先是一名警卫阻止这起事故的发生。

The null != a is an old practice in programming languages like Java,C++ (called as Yoda Conditions). As it is valid to write if (a = null) and accidentally assign null to the a so writing null first is a guard to stop this accident from happening.