为什么打印的Java阵列显示的存储器位置 [英] Why does printing a Java array show a memory location

问题描述

int[] answer= new int[map.size()];  
HashMap<String, Integer> map = new HashMap<String, Integer>();  

for (int j=0; j<answer.length;j++){  
    int x=map.get(keys.get(j));  
    answer[j]=x;  
}  

return answer  

当我打印 X 使用的System.out.println（X）在循环中，我得到的值 1，2，3 但是当我返回答案，并打印出来，我得到 [I @ 9826ac5 。任何想法，为什么？

When I print x using System.out.println(x) in the loop, I get values of 1, 2, 3 but when I return the answer and print it, I get [I@9826ac5. Any idea why?

推荐答案

I [是那种类类型为整型数组。打印出这个数组本身将打印类的类型 @ 再短的十六进制字符串，因为这是数组的哈希值code。这是因为一些你可能已经看到像对象@ 0b1ac20相同。这是作为默认<一href=\"http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/Object.html#toString%28%29\"><$c$c>toString()为对象 。

I[ is kind of the "class type" for an array of integer. Printing out this array itself will print the class type @ then a short hex string because that's the hash code of the array. It's the same as something you've probably seen like Object@0b1ac20. This is implemented as the default toString() for Object.

也许你想返回数组的特定元素或使用for循环打印整个数组？

Maybe you want to return a specific element of the array or print the whole array using a for loop?

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