原理：a,a++,fillStr(a, 9, false, "0");

1. 新建序列：

   create sequence seq_line
   minvalue 1
   maxvalue 999999999
   start with 1
   increment by 1
   cache 10
   NOCYCLE;

2. 获取该序列的下一个值：

   select seq_trip.nextval from dual

3. 获取编号：
   

 public static void main(String[] args) {  
         String outString="";  
         outString=fillStr("1", 9, false, "0");  
         System.out.println("false"+outString);  
         outString=fillStr("123", 9, true, "0");  
         System.out.println("true"+outString);  
           
        }
     public static String fillStr(String value, int count, boolean frontORback, String fillChar) {  
         String rtvalue = value;  
         if (rtvalue == null) {  
          rtvalue = "";  
          for (int i = 0; i < count; i++)  
           if (frontORback)  
            rtvalue = String.valueOf(rtvalue)  
              + String.valueOf(fillChar);  
           else  
            rtvalue = String.valueOf(fillChar)  
              + String.valueOf(rtvalue);  
         } else {  
          int len = rtvalue.length();  
          if (len > count) {  
           rtvalue = rtvalue.substring(0, count);  
          } else {  
           int a = count - len;  
           for (int i = 0; i < a; i++)  
            if (frontORback)  
             rtvalue = String.valueOf(rtvalue)  
               + String.valueOf(fillChar);   
            else  
             rtvalue = String.valueOf(fillChar)  
               + String.valueOf(rtvalue);  
          }  
         }  
         return rtvalue;  
        }