private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        JasperReport masterReport = null;
        try
        {
            masterReport = (JasperReport) JRLoader.loadObject(System.getProperty("user.dir") +
                            "/src/org/reportes/report3.jasper");
        }
        catch (JRException e) {}
        Map parametro = new HashMap();
        parametro.put("parametro",null);
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException ex) {

            Exceptions.printStackTrace(ex);
            }
        Connection conn = null;
        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/centromedico","root","");
            JasperPrint jasperPrint;
            try {
                jasperPrint = JasperFillManager.fillReport(masterReport, parametro, conn);
                JasperViewer jviewer = new JasperViewer(jasperPrint,false);
                jviewer.setVisible(true);
            } catch (JRException ex) {
                Exceptions.printStackTrace(ex);
            }

        } catch (SQLException ex) {

            Exceptions.printStackTrace(ex);
        }
        if (conn == null)
            try {
            conn.close();
        } catch (SQLException ex) {
            Exceptions.printStackTrace(ex);
        }
    }