code: public Object getSQLValue(String fieldname, Serializable fieldvalue) {
          if (this.cryptmap == null) return fieldvalue;
          CryptHandler handler = this.cryptmap.get(fieldname);
          if (handler == null) return fieldvalue;
          return handler.encrypt(fieldvalue);
      }
docs: 字段值转换成数据库的值
  
  @param fieldname  字段名
  @param fieldvalue 字段值
  
  @return Object