conn.java

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/*
 * Created on 2004-9-18
 *
 * To change the template for this generated file go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
package com.bwm.db;

import java.sql.*;

/**
 *class explain:Database connection<br>
 *set up name:	crazyadept<br>
 *set up time:	11/22/2004
 */
public class Conn {
	private static Connection con;
	private Statement  stmt;
	private ResultSet  rs;
	private PreparedStatement pstmt;
	private static int CON_COUNT=0;

	/**
     *method explain: Auto Connection DataBase<br>
	 *set up name:	crazyadept<br>
	 *change time:	12/20/2004
	 */
	public static synchronized Connection getCon()throws Exception{
		try{
			Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
			con=DriverManager.getConnection("jdbc:odbc:School","","");
			CON_COUNT++;
			return con;
		}catch(SQLException e){
			System.err.println(e.getMessage());
			throw e;
		}
	}

	/**
	 *return value:	in order select in SQL<br>
	 *set up name:	crazyadept<br>
	 *change time:	12/20/2004
	 */
	public Statement getStmtread(){
		try{
			con=getCon();
			stmt=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
			return stmt;
		}catch(Exception e){
			System.err.println(e.getMessage());
			e.printStackTrace();
		}
		return null;
	}

	/**
	 *return	value:	Data<br>
	 *parameter:		SQL select sentence<br>
	 *set up name:	crazyadept<br>
	 *change time:	11/29/2004
	 */
	public ResultSet getRs(String sql){
		try{
			stmt=getStmtread();
			rs=stmt.executeQuery(sql);
			return rs;
		}catch(Exception e){
			System.err.println(e.getMessage());
			e.printStackTrace();
		}
		return null;
	}

	/**
	 *return	value:	not in order select in str SQL<br>
	 *set up name:	crazyadept<br>
	 *set up time:	11/29/2004<br>
	 *change time:	11/29/2004
	 */
	public Statement getStmt(){
		try{
			con=getCon();
			stmt=con.createStatement();
			return stmt;
		}catch(Exception e){
			System.err.println(e.getMessage());
			e.printStackTrace();
		}
		return null;
	}

	/**
	 *return	value:	Connection count<br>
	 *set up name:	crazyadept<br>
	 *change time:	12/01/2004
	 */
	public int getConcount(){
		return CON_COUNT;
	}

	/**
	 *return	value:	DataBase pretreatment sentense<br>
	 *parameter:		like as SQL sentence<br>
	 *set up name:	crazyadept<br>
	 *set up time:	11/29/2004<br>
	 *change time:	11/29/2004
	 */
	public PreparedStatement getPstmt(String sql){
		try{
			con=getCon();
			pstmt=con.prepareStatement(sql);
			return pstmt;
		}catch(Exception e){
			System.err.println(e.getMessage());
			e.printStackTrace();
		}
		return null;
	}

	/**
	 *method explain: Close DataBase Connection<br>
	 *set up name:	crazyadept<br>
	 *set up time:	11/29/2004<br>
	 *change time:	11/29/2004
	 */
	public synchronized void close(){
		try{
			if(rs!=null){
				rs.close(); rs=null;
			}
		}catch(Exception e){
			System.err.println(e.getMessage());
			e.printStackTrace();
		}
		try{
			if(stmt!=null){
				stmt.close(); stmt=null;
			}
		}catch(Exception e){
			System.err.println(e.getMessage());
			e.printStackTrace();
		}
		try{
			if(con!=null){
				con.close(); con=null; CON_COUNT--;
			}
		}catch(Exception e){
			System.err.println(e.getMessage());
			e.printStackTrace();
		}
	}
}