package com.publish.shop.util.dao;import java.sql.*;import com.publish.shop.util.javabeans.*;import com.publish.shop.util.db.DbPool;public class SerialNoDAO {  public static int getSerialNo(Connection con,String serialType){        int serial = 0;        serial = getLastSerialNo(con,serialType);        System.out.println("serial:"+serial);        if(serial <= 0){            serial = 1;            createSerialNo(con,serialType,serial);        }        else{            serial ++;            updateSerialNo(con,serialType,serial);        }        System.out.println("serial next:"+getLastSerialNo(con,serialType));        return serial;    }    private static int getLastSerialNo(Connection con,String serialType){            int last = -1;            String sql = "select SerialNumber from Serial_Number";            sql += " where serialId='"+serialType+"'";            ResultSet rs = null;            Statement stmt = null;            try{                stmt = con.createStatement();                rs = stmt.executeQuery(sql);                while(rs.next())                  last = rs.getInt(1);            }catch(Exception posEx){            }            finally{              DbPool.closeResultSet(rs);              DbPool.closeStatement(stmt);            }            return last;        }        private static int createSerialNo(Connection con,String serialType, int serialNo){            int rs = 0;            String sql = "insert into Serial_Number(serialId,SerialNumber) values(";            sql += "'"+serialType+"',"+serialNo+")";            Statement stmt = null;            try{                stmt = con.createStatement();                rs = stmt.executeUpdate(sql);                con.commit();            }catch(Exception posEx){              posEx.printStackTrace();            }            finally{              DbPool.closeStatement(stmt);            }            return rs;        }        private static int updateSerialNo(Connection con,String serialType, int serialNo) {            int rs = 0;            String sql = "update Serial_Number";            sql += " set SerialNumber="+serialNo;            sql += " where serialId='"+serialType+"'";            Statement stmt = null;            try{                con = DbPool.getConnection();                stmt = con.createStatement();                rs = stmt.executeUpdate(sql);                con.commit();            }catch(Exception posEx){              posEx.printStackTrace();            }            finally{              DbPool.closeStatement(stmt);            }            return rs;        }}