java中合拼数组的三个方法

  介绍下java中三个合拼数组的方法

1) 使用apache common包
 

public static void main(String[] args) {

        String[] s1 = new String[]{"a", "b", "c"};
        String[] s2 = new String[]{"d", "e", "f"};

        String[] result = ArrayUtils.addAll(s1, s2);

        System.out.println(Arrays.toString(result));

		int [] int1 = new int[]{1,2,3};
        int[] int2 = new int[]{4,5,6};

        int[] result2 = ArrayUtils.addAll(int1, int2);

        System.out.println(Arrays.toString(result2));

2) 单纯的编写方法
 

 public static void main(String[] args) {

        String[] s1 = new String[]{"a", "b", "c"};
        String[] s2 = new String[]{"d", "e", "f"};
        String[] s3 = new String[]{"g", "h", "i"};

        String[] result = joinArrayGeneric(s1, s2, s3);

        System.out.println(Arrays.toString(result));

        int[] int1 = new int[]{1, 2, 3};
        int[] int2 = new int[]{4, 5, 6};
        int[] int3 = new int[]{7, 8, 9};

        int[] result2 = joinArray(int1, int2, int3);

        System.out.println(Arrays.toString(result2));

    }

    static <T> T[] joinArrayGeneric(T[]... arrays) {
        int length = 0;
        for (T[] array : arrays) {
            length += array.length;
        }

        //T[] result = new T[length];
        final T[] result = (T[]) Array.newInstance(arrays[0].getClass().getComponentType(), length);

        int offset = 0;
        for (T[] array : arrays) {
            System.arraycopy(array, 0, result, offset, array.length);
            offset += array.length;
        }

        return result;
    }

    static int[] joinArray(int[]... arrays) {
        int length = 0;
        for (int[] array : arrays) {
            length += array.length;
        }

        final int[] result = new int[length];

        int offset = 0;
        for (int[] array : arrays) {
            System.arraycopy(array, 0, result, offset, array.length);
            offset += array.length;
        }

        return result;
    }

	//create other overloaded primitive type - long, double...
	//static long[] joinArray(long[]... arrays) 
}