为啥只显示表格不显示数据呢

@FXML

private void initButton1()
{

   table.getItems();

   showData();

}
protected void showData() {

   if(generateDate1()!=null){

                 materialList = generateDate1();
              }

                List1.addAll(materialList);

                table.setItems(List1);
         }

@FXML

private List generateDate1() {

   List<MaterialInfo> miList = new ArrayList<MaterialInfo>();
   try{

       Class.forName("com.mysql.jdbc.Driver");
    }catch(ClassNotFoundException cne){
        cne.printStackTrace();
    }
    String dburl="jdbc:mysql://127.0.0.1:3306/bookstore";
    String sql="SELECT * FROM books WHERE User_ID=1000002";
    MaterialInfo mi = null;
    try(Connection conn=
            DriverManager.getConnection(dburl,"root","12345");
            Statement stmt =conn.createStatement();
            ResultSet rst = stmt.executeQuery(sql))
            {mi = new MaterialInfo();
            mi.setUser_ID(rst.getInt(1));
            mi.setProduct_ID(rst.getString(2));
            mi.setGender(rst.getString(3));
            mi.setAge(rst.getString(4));
            mi.setOccupation(rst.getInt(5));
            mi.setCity_Category(rst.getString(6));
            mi.setStay_In_Current_City_Years(rst.getString(7));
            mi.setMarital_Status(rst.getInt(8));
            mi.setProduct_Category_1(rst.getInt(9));
            mi.setProduct_Category_2(rst.getFloat(10));
            mi.setProduct_Category_3(rst.getFloat(11));
            mi.setPurchase(rst.getInt(12)); miList.add(mi);

            }
            }catch(SQLException se){
            se.printStackTrace();
        }
    return miList;

}