identity.java~1~

封装了SQL、Socket、WAP、MIME等功能的通用组件

package com.lazybug.sql;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2004</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */
import java.sql.*;

public class Identity
{
    public final static String TABLE = "tbl_identity";//序列表的名称

    public static int getIdentity(String tblname)
    {
        int value=-1;
        DBConnection dbconn = DBConnectionManager.getConnection();
        Connection conn = dbconn.get();
        PreparedStatement pstmt = null ;
        ResultSet rs = null ;

        try
        {
            String psql = "select tblid from "+TABLE+" where tblname=?" ;
            pstmt = conn.prepareStatement(psql) ;
            pstmt.setString(1, tblname) ;
            rs = pstmt.executeQuery() ;
            if ( rs.next() )
            {
                value = rs.getInt("tblid");
            }
            rs.close();

            String updateSql="update "+TABLE+" set tblid=tblid+1 where tblname=?";
            pstmt = conn.prepareStatement(updateSql) ;
            pstmt.setString(1,tblname);
            pstmt.executeUpdate();
            pstmt.close() ;
        }
        catch (SQLException ex)
        {
            return -1;
        }
        finally
        {
            DBConnectionManager.freeConnection(dbconn);
        }
        return value;
    }

    public synchronized static int getSequence(String tablname, String tablekey)
    {
        int value=-1;
        DBConnection dbconn = DBConnectionManager.getConnection();
        Connection conn = dbconn.get();
        PreparedStatement pstmt = null ;
        ResultSet rs = null ;

        try
        {
            String psql = "select max("+tablekey+") from "+tablname;
            pstmt = conn.prepareStatement(psql) ;
            rs = pstmt.executeQuery() ;
            if ( rs.next() )
            {
                value = rs.getInt(1);
                value += 1;
            }
            rs.close();
            pstmt.close() ;
        }
        catch (SQLException ex)
        {
            return -1;
        }
        finally
        {
            DBConnectionManager.freeConnection(dbconn);
        }
        return value;
    }

}