网络购物中心项目源码的设计

package com.tools; import java.sql.*; import java.io.*; import java.util.*; public class ConnDB { public Connection conn = null; public Statement stmt = null; public ResultSet rs = null; private static String propFileName = "/com/connDB.properties"; // 指定资源文件保存的位置 private static Properties prop = new Properties(); private static String dbClassName = "com.microsoft.sqlserver.jdbc.SQLServerDriver"; private static String dbUrl = "jdbc:sqlserver://localhost:1433;DatabaseName=db_shop"; private static String dbUser = "sa"; private static String dbPwd = ""; public ConnDB() { try { InputStream in = getClass().getResourceAsStream(propFileName); prop.load(in); // 通过输入流对象加载Properties文件 dbClassName = prop.getProperty("DB_CLASS_NAME"); // 获取数据库驱动 dbUrl = prop.getProperty("DB_URL", dbUrl); dbUser = prop.getProperty("DB_USER", dbUser); dbPwd = prop.getProperty("DB_PWD", dbPwd); } catch (Exception e) { e.printStackTrace(); // 输出异常信息 } } public static Connection getConnection() { Connection conn = null; try { Class.forName(dbClassName).newInstance(); conn = DriverManager.getConnection(dbUrl, dbUser, dbPwd); } catch (Exception ee) { ee.printStackTrace(); } if (conn == null) { System.err .println("警告: DbConnectionManager.getConnection() 获得数据库链接失败.\r\n\r\n链接类型:" + dbClassName + "\r\n链接位置:" + dbUrl + "\r\n用户/密码" + dbUser + "/" + dbPwd); } return conn; } /* * 功能：执行查询语句 */ public ResultSet executeQuery(String sql) { try { // 捕捉异常 conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY); rs = stmt.executeQuery(sql); } catch (SQLException ex) { System.err.println(ex.getMessage()); // 输出异常信息 } return rs; // 返回结果集对象 } /* * 功能:执行更新操作 */ public int executeUpdate(String sql) { int result = 0; // 定义保存返回值的变量 try { // 捕捉异常 conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY); result = stmt.executeUpdate(sql); // 执行更新操作 } catch (SQLException ex) { result = 0; // 将保存返回值的变量赋值为0 } try { stmt.close(); } catch (SQLException ex1) { } return result; // 返回保存返回值的变量 } public int executeUpdate_id(String sql) { int result = 0; // 定义保存返回值的变量 try { // 捕捉异常 conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY); result = stmt.executeUpdate(sql); // 执行更新操作 // 获取刚刚插入记录的自动编号 String ID = "select @@IDENTITY as id"; rs = stmt.executeQuery(ID); if (rs.next()) { int autoID = rs.getInt("id"); result = autoID; } } catch (SQLException ex) { result = 0; } return result; // 返回刚刚插入的自动编号 } /* * 功能:关闭数据库的连接 */ public void close() { try { // 捕捉异常 if (rs != null) { // 当ResultSet对象的实例rs不为空时 rs.close(); // 关闭ResultSet对象 } if (stmt != null) { // 当Statement对象的实例stmt不为空时 stmt.close(); // 关闭Statement对象 } if (conn != null) { // 当Connection对象的实例conn不为空时 conn.close(); // 关闭Connection对象 } } catch (Exception e) { e.printStackTrace(System.err); // 输出异常信息 } } }