try {
            Class.forName("net.sourceforge.jtds.jdbc.Driver");            
            conn = DriverManager.getConnection("jdbc:jtds:sqlserver://127.0.0.1:1433/book","sa","sa");
//          Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
//          conn = DriverManager.getConnection("jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=book","sa","sa");
            System.out.println("连接成功");
        } catch (ClassNotFoundException ex) {
            System.out.println(ex.getMessage() + "驱动错误");
        }
        catch (SQLException ex) {
            System.out.println(ex.getMessage() + "路径错误");
        }