JSP图书管理系统MVC模式的

package bean.Databaseconn; import java.sql.*; public class DataBaseConn { private static final int i = 0; String driver="com.microsoft.jdbc.sqlserver.SQLServerDriver"; String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=library"; static ResultSet rs=null; static Connection conn=null; static Statement stmt=null; static PreparedStatement pstmt = null ; public DataBaseConn() { try { //注册数据库驱动 Class.forName(driver).newInstance(); //建立数据库连接 conn=DriverManager.getConnection(url,"sa","sa"); } catch(Exception e) { e.printStackTrace(); } } public Connection getConn() { return conn; } public boolean checkadminlogin(String sql) { boolean flg=false; try { stmt=conn.createStatement(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { rs=stmt.executeQuery(sql); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { if(rs.next()) { flg=true; } else { flg=false; } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return flg; } //图书类型添加 public boolean booktypeadd(String sql) { boolean mm=false; if(mm=true) { try { stmt=conn.createStatement(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { stmt.executeUpdate(sql); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } else { return false; } return mm; } //图书类型查询 public ResultSet getRs_booktype() throws SQLException { String sql="select * from booktype"; Statement stmt=conn.createStatement(); ResultSet rs=stmt.executeQuery(sql); return rs; } public boolean update(String sql) { try { stmt=conn.createStatement(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { int i = stmt.executeUpdate(sql); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(i>0) { return true; } else { return false; } } }