比较 Java 中的整数数组.为什么 == 不起作用? [英] Comparing integer Arrays in Java. Why does not == work?

问题描述

我正在学习 Java，只是想出了一个关于该语言的微妙事实:如果我声明两个具有相同元素的整数数组并使用 == 比较它们，结果是 false.为什么会这样?比较不应该评估为 true 吗?

I'm learning Java and just came up with this subtle fact about the language: if I declare two integer Arrays with the same elements and compare them using == the result is false. Why does this happen? Should not the comparison evaluate to true?

public class Why {

    public static void main(String[] args) {
        int[] a = {1, 2, 3};
        int[] b = {1, 2, 3};

        System.out.println(a == b);
    }

}

提前致谢！

推荐答案

使用Arrays.equals(arr1, arr2) 方法.

Use Arrays.equals(arr1, arr2) method.

== 运算符 只是检查两个引用是否指向同一个对象.

The == operator just checks if two references point to the same object.

测试:

int[] a = {1, 2, 3};
int[] b = a;    
System.out.println(a == b);   // returns true as b and a refer to the same array  

int[] a = {1, 2, 3};
int[] b = {1, 2, 3};
System.out.println(Arrays.equals(a, b));   //returns true as a and b are meaningfully equal

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