Jsp+Servlet+JavaBean+JDBC简单登录实例

package util; 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 //连接第一种办法 public static Statement getStatment(){ try{ driver="com.microsoft.sqlserver.jdbc.SQLServerDriver"; url="jdbc:sqlserver://192.168.4.133:1433;databaseName=xc"; user="sa"; password="123.com123.com"; Class.forName(driver); conn=DriverManager.getConnection(url, user, password); System.out.println("-------连接成功------"); }catch(ClassNotFoundException e){ e.printStackTrace(); System.out.println("db: " + e.getMessage()); }catch(SQLException ex){ ex.printStackTrace(); System.err.println("db.getconn(): " + ex.getMessage()); } return null; } //连接第二种办法 /*public static Statement getStatment(){ try{ Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); conn=DriverManager.getConnection("jdbc:sqlserver://192.168.4.133:1433;databaseName=xc", "sa", "123.com123.com"); System.out.println("-------连接成功------"); }catch(ClassNotFoundException e){ e.printStackTrace(); System.out.println("db: " + e.getMessage()); }catch(SQLException ex){ ex.printStackTrace(); System.err.println("db.getconn(): " + ex.getMessage()); } return null; }*/ //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 sqlexception) { System.err.println("db.executeInset:" + sqlexception.getMessage()); }finally{ } } //执行删除 public void doDelete(String sql) { try { stmt = conn.createStatement(); int i = stmt.executeUpdate(sql); } catch(SQLException sqlexception) { System.err.println("db.executeDelete:" + sqlexception.getMessage()); } } //执行更新 public void doUpdate(String sql) { try { stmt = conn.createStatement(); int i = stmt.executeUpdate(sql); } catch(SQLException sqlexception) { System.err.println("db.executeUpdate:" + sqlexception.getMessage()); } } //查询结果集 public ResultSet doSelect(String sql) { try { conn=DriverManager.getConnection(url,user,password); stmt = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY); rs = stmt.executeQuery(sql); System.out.println("取得结果集"); } catch(SQLException sqlexception) { System.err.println("db.executeQuery: " + sqlexception.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(); ResultSet rs=db.doSelect("select * from db_user where userName='admin'"); try { while(rs.next()){ System.out.println(rs.getInt(1)); System.out.println(rs.getString(3)); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } */ }