比较 Java 中的两个基元数组？
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Compare two arrays of primitives in Java?
提问by Mark Renouf
I know about Arrays.deepEquals(Object[], Object[]) but this doesn't work for primitive types (due limitations of arrays and autoboxing, see this related post).
我知道 Arrays.deepEquals(Object[], Object[]) 但这不适用于原始类型（由于数组和自动装箱的限制，请参阅此相关帖子）。
With that in mind, is this the most efficient approach?
考虑到这一点，这是最有效的方法吗？
boolean byteArrayEquals(byte[] a, byte[] b) {
if (a == null && b == null)
return true;
if (a == null || b == null)
return false;
if (a.length != b.length)
return false;
for (int i = 0; i < a.length; i++) {
if (a[i] != b[i])
return false;
}
return true;
}
回答by Jon Skeet
Change your first comparison to be:
将您的第一个比较更改为：
if (a == b)
return true;
This not only catches the "both null" cases, but also "compare an array to itself" case.
这不仅可以捕获“两个为空”的情况，还可以捕获“将数组与自身进行比较”的情况。
However, for a simpler alternative - use Arrays.equalswhich has overloads for each primitive type. (The implementation is very similar to yours, except it hoists the array length out of the loop. On .NET that can be an anti-optimization, but I guess the JRE library implementors probably know better for the JVM :)
但是，对于更简单的替代方案 - 使用Arrays.equals每个原始类型都有重载。（该实现与您的非常相似，除了它将数组长度提升到循环之外。在 .NET 上，这可能是一种反优化，但我猜 JRE 库实现者可能更了解 JVM :)
回答by unwind
回答by EpicPandaForce
I don't know if this will help anyone, but this seems to be working:
我不知道这是否会帮助任何人，但这似乎有效：
if(type == type_BooleanArray) {
boolean eq = Arrays.equals((boolean[]) thisObj, (boolean[]) thatObj);
if(!eq) {
return false;
}
} else if(type == type_ByteArray) {
boolean eq = Arrays.equals((byte[]) thisObj, (byte[]) thatObj);
if(!eq) {
return false;
}
} else if(type == type_ShortArray) {
boolean eq = Arrays.equals((short[]) thisObj, (short[]) thatObj);
if(!eq) {
return false;
}
} else if(type == type_CharArray) {
boolean eq = Arrays.equals((char[]) thisObj, (char[]) thatObj);
if(!eq) {
return false;
}
} else if(type == type_IntArray) {
boolean eq = Arrays.equals((int[]) thisObj, (int[]) thatObj);
if(!eq) {
return false;
}
} else if(type == type_LongArray) {
boolean eq = Arrays.equals((long[]) thisObj, (long[]) thatObj);
if(!eq) {
return false;
}
} else if(type == type_FloatArray) {
boolean eq = Arrays.equals((float[]) thisObj, (float[]) thatObj);
if(!eq) {
return false;
}
} else if(type == type_DoubleArray) {
boolean eq = Arrays.equals((double[]) thisObj, (double[]) thatObj);
if(!eq) {
return false;
}
} else {
if(!thisObj.equals(thatObj)) {
return false;
}
}
Apparently array.equals(otherArray)does a array == otherArray, and not what you would expect.
显然array.equals(otherArray)做了 a array == otherArray，而不是你所期望的。
