Java两个数组合并

以下是Java中合并两个数组的三种方法：
1. 使用Java arraycopy()方法

int[] arr1 = {1, 2, 3};
int[] arr2 = {4, 5, 6};
int[] result = new int[arr1.length + arr2.length];
System.arraycopy(arr1, 0, result, 0, arr1.length);
System.arraycopy(arr2, 0, result, arr1.length, arr2.length);
System.out.println(Arrays.toString(result)); // 输出：[1, 2, 3, 4, 5, 6]

2. 不使用arraycopy()方法，使用循环遍历

int[] arr1 = {1, 2, 3};
int[] arr2 = {4, 5, 6};
int[] result = new int[arr1.length + arr2.length];
int pos = 0;
for (int element : arr1) {
    result[pos] = element;
    pos++;
}
for (int element : arr2) {
    result[pos] = element;
    pos++;
}
System.out.println(Arrays.toString(result)); // 输出：[1, 2, 3, 4, 5, 6]

3. 使用Java Stream API

int[] arr1 = {1,2, 3};
int[] arr2 = {4, 5, 6};
int[] result = IntStream.concat(Arrays.stream(arr1), Arrays.stream(arr2)).toArray();
System.out.println(Arrays.toString(result)); // 输出：[1, 2, 3, 4, 5, 6]