布尔运算符的差异：& vs&&和| vs || [英] Differences in boolean operators: & vs && and | vs ||

问题描述

我知道&& 和 || 的规则，但是什么& 和 | ？请用一个例子向我解释。

I know the rules for && and || but what are & and |? Please explain these to me with an example.

推荐答案

这些是按位AND和按位OR运算符。

Those are the bitwise AND and bitwise OR operators.

int a = 6; // 110
int b = 4; // 100

// Bitwise AND    

int c = a & b;
//   110
// & 100
// -----
//   100

// Bitwise OR

int d = a | b;
//   110
// | 100
// -----
//   110

System.out.println(c); // 4
System.out.println(d); // 6

感谢Carlos指出Java语言规范（ 15.22.1 ，15.22.2 ）根据操作员的输入，了解操作员的不同行为。

Thanks to Carlos for pointing out the appropriate section in the Java Language Spec (15.22.1, 15.22.2) regarding the different behaviors of the operator based on its inputs.

实际上，当两个输入都是布尔值时，运算符被认为是布尔逻辑运算符，其行为类似于Conditional-And（&& ）和Conditional-Or（ || ）运算符除了它们没有短路这样的事实，所以以下是安全的：

Indeed when both inputs are boolean, the operators are considered the Boolean Logical Operators and behave similar to the Conditional-And (&&) and Conditional-Or (||) operators except for the fact that they don't short-circuit so while the following is safe:

if((a != null) && (a.something == 3)){
}

这不是：

if((a != null) & (a.something == 3)){
}

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