求这题编程题源码！⋯⋯⋯⋯

⋯⋯⋯⋯求源码⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯

    @Override
    public <T> String join(T[] ts, String delimiter) {
        if (delimiter == null) {
            delimiter = "";
        }
        if (ts.length < 1) {
            return delimiter;
        }

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < ts.length - 1; i++) {
            sb.append(ts[i].toString()).append(delimiter);
        }
        sb.append(ts[ts.length - 1]);
        return sb.toString();
    }

    @Override
    public <T> String join(Collection<T> ts, String delimiter) {
        if (delimiter == null) {
            delimiter = "";
        }
        if (ts.size() < 1) {
            return delimiter;
        }

        StringBuilder sb = new StringBuilder();
        Iterator<T> iter = ts.iterator();
        while (iter.hasNext()) {
            sb.append(iter.next().toString()).append(delimiter);
        }
        sb.delete(sb.length() - delimiter.length(), sb.length());
        return sb.toString();
    }

    public static void main(String[] args) {
        ElementJoiner ej = new ElementJoinerImpl();
        String arr = ej.join(new Integer[]{1, 2, 3}, "/");
        System.out.println(arr);

        List<Integer> list = new LinkedList<>();
        list.add(new Integer(1));
        list.add(new Integer(2));
        list.add(new Integer(3));
        String l = ej.join(list, "~ ");
        System.out.println(l);
    }

 public <T> String join(T[] ts, String delimiter)
{
String r = "";
for (int i = 0; i < ts.length; i++)
{
if (i == 0) r += ts[0].toString(); else r += (delimiter + ts[i].toString());
}
return r;
}