JAVA生成主键ID的代码

用时间处理生成的 

public static String getNextID(String table){
  String id="";
  if(table.length()>4) table=table.substring(0, 4);
  int year=new Timestamp(System.currentTimeMillis()).getYear();
  int month=(new Timestamp(System.currentTimeMillis()).getMonth()+1);
  int day=new Timestamp(System.currentTimeMillis()).getDate();
  int hours=new Timestamp(System.currentTimeMillis()).getHours();
  int minte=new Timestamp(System.currentTimeMillis()).getMinutes();
  long time=new Timestamp(System.currentTimeMillis()).getTime();
  
  String num=String.valueOf(year).substring(1)+String.valueOf(month)+String.valueOf(day)
  +String.valueOf(hours)+String.valueOf(minte)+String.valueOf(time).substring(8, 13);
  
  id=table+num;
  
  return id;
 }