Java实现把两个数组合并为一个的方法总结

static String[] concat(String[] a, String[] b) {
  String[] c= new String[a.length+b.length];
  System.arraycopy(a, 0, c, 0, a.length);
  System.arraycopy(b, 0, c, a.length, b.length);
  return c;
}

String[] both = concat(first, second);

public static <T> T[] concat(T[] first, T[] second) {
 T[] result = Arrays.copyOf(first, first.length + second.length);
 System.arraycopy(second, 0, result, first.length, second.length);
 return result;
}

public static <T> T[] concatAll(T[] first, T[]... rest) {
 int totalLength = first.length;
 for (T[] array : rest) {
  totalLength += array.length;
 }
 T[] result = Arrays.copyOf(first, totalLength);
 int offset = first.length;
 for (T[] array : rest) {
  System.arraycopy(array, 0, result, offset, array.length);
  offset += array.length;
 }
 return result;
}

String[] both = concat(first, second);
String[] more = concat(first, second, third, fourth);

private static <T> T[] concat(T[] a, T[] b) {
  final int alen = a.length;
  final int blen = b.length;
  if (alen == 0) {
    return b;
  }
  if (blen == 0) {
    return a;
  }
  final T[] result = (T[]) java.lang.reflect.Array.
      newInstance(a.getClass().getComponentType(), alen + blen);
  System.arraycopy(a, 0, result, 0, alen);
  System.arraycopy(b, 0, result, alen, blen);
  return result;
}