jsp+servlet+javabean案例

package com.zhaobp.db; import java.io.*; import java.sql.*; public class DBConn { public static String driver;//定义驱动 public static String url;//定义URL public static String user;//定义用户名 public static String password;//定义密码 public static Connection conn;//定义连接 public static Statement stmt;//定义STMT public ResultSet rs;//定义结果集 //设置CONN static{ try { driver="oracle.jdbc.driver.OracleDriver"; url="jdbc:oracle:thin:@localhost:1521:orcl"; user="scott"; password="tiger"; Class.forName(driver); conn = DriverManager.getConnection(url,user,password); System.out.println("-------连接成功------"); } catch(ClassNotFoundException e) { e.printStackTrace(); System.err.println("db: " + e.getMessage()); } catch(SQLException e) { System.err.println("db.getconn(): " + e.getMessage()); } } //构造函数，默认加裁配置文件为jdbc.driver public DBConn(){ this.conn=this.getConn(); } //返回Conn public Connection getConn(){ return this.conn; } //执行插入 public void doInsert(String sql) { try { stmt = conn.createStatement(); int i = stmt.executeUpdate(sql); } catch(SQLException e) { System.err.println("db.executeInset:" + e.getMessage()); }finally{ } } //执行删除 public void doDelete(String sql) { try { stmt = conn.createStatement(); int i = stmt.executeUpdate(sql); } catch(SQLException e) { System.err.println("db.executeDelete:" + e.getMessage()); } } //执行更新 public void doUpdate(String sql) { try { stmt = conn.createStatement(); int i = stmt.executeUpdate(sql); } catch(SQLException e) { System.err.println("db.executeUpdate:" + e.getMessage()); } } //查询结果集 public ResultSet doSelect(String sql) { try { conn=DriverManager.getConnection(url,user,password); stmt = conn.createStatement(); rs = stmt.executeQuery(sql); System.out.println("取得结果集啊:"+sql); } catch(SQLException e) { System.err.println("db.executeQuery:会是这个吗 " + e.getMessage()); } return rs; } /** *关闭数据库结果集，数据库操作对象，数据库链接 @Function: Close all the statement and conn int this instance and close the parameter ResultSet @Param: ResultSet @Exception: SQLException,Exception **/ public void close(ResultSet rs) throws SQLException, Exception { if (rs != null) { rs.close(); rs = null; } if (stmt != null) { stmt.close(); stmt = null; } if (conn != null) { conn.close(); conn = null; } } /** *关闭数据库操作对象，数据库连接对象 * Close all the statement and conn int this instance * @throws SQLException * @throws Exception */ public void close() throws SQLException, Exception { if (stmt != null) { stmt.close(); stmt = null; } if (conn != null) { conn.close(); conn = null; } } //测试类 // public static void main(String []args){ // DBConn db=new DBConn(); // db.getConn(); // db.doInsert("insert into user (username,password) values('zhoabp','111')"); // // } }