basedao.java

jsp/servlet/javaBean应用：网上购书系统

package dao;

import java.sql.*;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

public class BaseDao {
	
	public final static String DRIVER="com.microsoft.sqlserver.jdbc.SQLServerDriver";
	public final static String URL="jdbc:sqlserver://localhost:1433;DatabaseName=books";
    public final static String DBNAME="sa";
	public final static String DBPASS="hjb";
	
	//连接数据库
	public Connection getConn(){
		
		Connection conn=null;
		
		try{
			Class.forName(DRIVER);
			conn = DriverManager.getConnection(URL,DBNAME,DBPASS);
		}catch(Exception ex){
			ex.printStackTrace();
			System.out.println(ex.getMessage());
		}
		return conn;
	}
	
	//关闭数据库
	public void closeConn(Connection conn,PreparedStatement psmt,ResultSet rest){
		try{
			if(conn!=null && (!conn.isClosed())){
				conn.close();
			}
		}catch(SQLException sexC){
			sexC.printStackTrace();
			System.out.println(sexC.getMessage());
		}
		try{
			if(psmt!=null){
				psmt.close();
				psmt=null;
			}
		}catch(SQLException sexP){
			sexP.printStackTrace();
			System.out.println(sexP.getMessage());
		}
		try{
			if(rest!=null){
				rest.close();
				rest=null;
			}
		}catch(SQLException sexR){
			sexR.printStackTrace();
			System.out.println(sexR.getMessage());
		}
	}
	
	//增、删、改数据库
	public int executeDB(String sql,String[] param){
		int num=0;
		Connection conn=null;
		PreparedStatement psmt=null;
		try{
			conn=getConn();
			psmt=conn.prepareStatement(sql);
			if(param!=null){
				for(int i=0;i<param.length;i++){
					psmt.setString(i+1, param[i]);
				}
			}
			num=psmt.executeUpdate();
		}catch(SQLException sexE){
			sexE.printStackTrace();
			System.out.println(sexE.getMessage());
		}finally{
			closeConn(conn,psmt,null);
		}
		return num;
	}
}