public class Mail implements Cloneable {  
  private String receiver;  
  private String subject;  
  private String content;  
  private String tail;  
  public Mail(EventTemplate et) {    
    this.tail = et.geteventContent();    
    this.subject = et.geteventSubject();
  }  
  @Override
  public Mail clone() {
    Mail mail = null;    
  try {
      mail = (Mail) super.clone();      
    } catch (CloneNotSupportedException e) {      
    // TODO Auto-generated catch block
      e.printStackTrace();
    }    return mail;
  }
//get、set.....
}

public static void main(String[] args) {
  int i = 0;
  int MAX_COUNT = 10;
  EventTemplate et = 
new EventTemplate("邀请函（不变）", "婚嫁生日啥的....（不变部分）");
  Mail mail = new Mail(et);  
  while (i < MAX_COUNT) {
    Mail cloneMail = mail.clone();
    cloneMail.setContent("XXX先生（女士）（变化部分）"
   + mail.getTail());
    cloneMail.setReceiver("每个人的邮箱地址...com（变化部分）");
    sendMail(cloneMail);
    i++;
  }

}

private String receiver;
private String subject;
private String content;
private String tail;
private ArrayList<String> ars;

try {
    mail = (Mail) super.clone();    
    mail.ars = (ArrayList<String>)this.ars.clone();
   } catch (CloneNotSupportedException e) {
     e.printStackTrace();
}