java项目实战-超市管理系统（五）数据库源码与分析

第一个包是page包，已经在这里分享过了，现在来分享db包的源码

package duan.db;

import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Connection;
/**
 * 连接mysql数据库
 * @author duan
 */
public final class DbConn
{
	public static  Connection getconn()
	{
		Connection conn = null;
		
		String user   = "root";
		String passwd = "******";
		String url = "jdbc:mysql://127.0.0.1:3306/shop";
		
		//已加载完驱动
		try
		{
			Class.forName("com.mysql.jdbc.Driver"); 
			conn = DriverManager.getConnection(url,user,passwd);
		}catch (SQLException e)
		{
			e.printStackTrace();
		}
		catch (ClassNotFoundException e)
		{
			e.printStackTrace();
		}
		return conn;
	}

}

package duan.db;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * 关闭操作数据库时产生的资源流
 * @author duan
 */
public final class DbClose
{
	/**
	 * 关闭 添加功能 资源
	 * @param pstmt,rs,conn
	 */
		public static void addClose(PreparedStatement pstmt, Connection conn)
		{
			/*
			 * 多个 try-catch 出发点：安全
			 */
			try
			{
				if (pstmt != null)
				{
					pstmt.close();
				}
			} catch (SQLException e1)
			{
				e1.printStackTrace();
			}
			try
			{
				if (conn != null)
				{
					conn.close();
				}
			} catch (SQLException e)
			{
				e.printStackTrace();
			}
		}
		
		/**
		 * 关闭资源
		 * @param pstmt,rs,conn
		 */
		public static void queryClose(PreparedStatement pstmt, ResultSet rs, Connection conn)
		{
			try
			{
				if (pstmt != null)
				{
					pstmt.close();
				}
			} catch (SQLException e1)
			{
				e1.printStackTrace();
			}
			try
			{
				if (rs != null )
				{
					rs.close();
				}
			} catch (SQLException e1)
			{
				e1.printStackTrace();
			}
			try
			{
				if (conn != null)
				{
					conn.close();
				}
			} catch (SQLException e)
			{
				e.printStackTrace();
			}
		}
		
}

String passwd = "******";