留言板代码（带数据库）

package dbconn; import java.sql.*; /** * 这个类是用于连接数据库，生成连接对象 * @author cy * @version 1.0 */ public class DBConn { private final String DRIVER="com.microsoft.jdbc.sqlserver.SQLServerDriver"; private final String URL="jdbc:microsoft:sqlserver://localhost:1433;databasename=student"; private final String USERNAME="sa"; private final String PWD="sa"; private Connection conn=null; private PreparedStatement pstat=null; private ResultSet rs=null; /** * */ public DBConn(){ } /** * * @return Connection 返回生成的连接对象 */ public Connection getConn(){ try { Class.forName(DRIVER); conn=DriverManager.getConnection(URL,USERNAME,PWD); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block System.out.println("注册驱动失败"+e.toString()); } catch (SQLException e) { // TODO Auto-generated catch block System.out.println("数据库连接失败"+e.toString()); } return conn; } /** * * @param sql待查询的sql语句 * @return 返回查询结果记录集 */ public ResultSet executeQuery(String sql){ try { pstat=conn.prepareStatement(sql); rs=pstat.executeQuery(); return rs; } catch (SQLException e) { // TODO Auto-generated catch block System.out.println("数据库操作失败"); return rs; } } /** * * @param sql 待操作的sql语句 * @return 返回整型值 */ public int executeUpdate(String sql){ int flag=0; try { pstat=conn.prepareStatement(sql); flag=pstat.executeUpdate(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return flag; } public void close(){ try { if(rs!=null){ rs.close(); } if(pstat!=null){ pstat.close(); } if(conn!=null){ conn.close(); } }catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }