字符串拼接練習

package string;

public class Test001 {
 public static void main(String[] args) {
  String[] arr = { "ab", "cd", "ef" };
  System.out.println(String.join("-", arr));
  System.out.println(regroup("-", arr));
 }

 public static String regroup(String delimiter, String... args) {
  StringBuffer temp = new StringBuffer();
  boolean flag = false;

  for (String s : args) {
   if (flag) {
    temp.append(delimiter);
    temp.append(s);
   } else {
    temp.append(s);
    flag = true;
   }
  }
  return temp.toString();
 };

}