public class test {
  public static void main(String[] args) {
    // 创建对象
    StringBuffer sb = new StringBuffer();
    sb.append("dzm");
    // 将 StringBuffer 转换为 String
    String str = sb.toString();
    // String 转换为 StringBuffer
    StringBuffer sb2 = new StringBuffer(str);
    // 输出
    System.out.println(str);
    System.out.println(sb2);
  }
}