thymeleaf iterates the map collection

@WebServlet("/index")public class Ceshi extends ViewBaseServlet {static Map p1=new HashMap();static {p1.put("1",new Pring(1,"banana","20"));p1.put("2",new Pring(2, "apple","12"));p1.put("3",new Pring(3, "Watermelon","30"));}@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {HttpSession session = req.getSession();session.setAttribute("p1", p1);super.processTemplate("index",req,resp);}}

via

th:each="item:${session.p1}"traverse map collection

item.value.id Get the value of the map collection variable id

item.getKey() Get the key of the current map

Use this to save data

HttpSession session = req.getSession();session.setAttribute("p1", p1);

You can also do without static