basedao.java

jsp/servlet/javaBean:通讯录

package common;

import java.sql.*;
import javax.naming.*;
import javax.sql.*;

public class BaseDao {
	
	// 连接数据库
	public Connection getConn(){
		Connection conn=null;
		try{
			Context ic=new InitialContext();
			DataSource source=(DataSource)ic.lookup("java:comp/env/jdbc/addressBook");
			conn=source.getConnection();
		}catch(SQLException se){
			se.printStackTrace();
			System.out.println(se.getMessage());
		}catch(NamingException ne){
			ne.printStackTrace();
			System.out.println(ne.getMessage());
		}
		return conn;
	}
	
	// 关闭数据库
	public void closeConn(Connection conn,PreparedStatement psmt,ResultSet rest){
		try{
			if(psmt!=null){
				psmt.close();
				psmt=null;
			}
		}catch(SQLException ep){
			ep.printStackTrace();
			System.out.println(ep.getMessage());
		}
		try{
			if(rest!=null){
				rest.close();
				rest=null;
			}
		}catch(SQLException er){
			er.printStackTrace();
			System.out.println(er.getMessage());
		}
		try{
			if(conn!=null && (!conn.isClosed())){
				conn.close();
			}
		}catch(SQLException ec){
			ec.printStackTrace();
			System.out.println(ec.getMessage());
		}
	}
	
	//更新数据库
	public int changeDB(String sql,String[] param){
		int i=0;
		PreparedStatement psmt=null;
		Connection conn=null;
		try{
			conn=getConn();
			psmt=conn.prepareStatement(sql);
			if(param!=null){
				for(int j=0;j<param.length;j++){
					psmt.setString(i+1, param[i]);
				}
			}
			i=psmt.executeUpdate();
		}catch(Exception ex){
			ex.printStackTrace();
			System.out.println(ex.getMessage());
		}finally{
			closeConn(conn,psmt,null);
		}
		return i;
	}
}