Servlet takes the value and passes it to jsp, but the output is null. What went wrong? - Codes Helper

jsp"s mall system, after the background servlet takes the commodity data of the database, it is forwarded to jsp to render, but the foreground rendering is always blank. After looking for it for a long time, it does not find a problem and does not report an error. Here is the code:

ListProductServlet.java

package sh.shop.web.servlet.manager;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import sh.shop.domain.Product;
import sh.shop.exception.ListProductException;
import sh.shop.service.ProductService;

@WebServlet("/listProduct")
/**
 * 
 * servlet
 */
public class ListProductServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
            try {
                // 1.service
                ProductService service = new ProductService();
                // 2.servicelistAll()
                List<Product> list = service.listAll();
                // 3.request
                request.setAttribute("list", list);
                // 4.list.jsp
                request.getRequestDispatcher("/admin/products/list.jsp").forward(
                                request, response);
                return;
            } catch (ListProductException e) {
                    e.printStackTrace();
                    response.getWriter().write(e.getMessage());
                    return;
            }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request,response);
    }
}

ProductService.java

package sh.shop.service;

import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import sh.shop.exception.AddProductException;
import sh.shop.dao.ProductDao;
import sh.shop.domain.Product;
import sh.shop.exception.ListProductException;


@WebServlet("/ProductService")
public class ProductService {
    private ProductDao dao = new ProductDao();

    public List<Product> listAll() throws ListProductException {
        try {
            List<Product> list = dao.listAll();
            return list;
        } catch (SQLException e) {
            e.printStackTrace();
            throw new ListProductException("");
        }
    }
    
    public void addProduct(Product p) throws AddProductException {
        try {
            dao.addProduct(p);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new AddProductException("");
        }
    }
    
}

ProductDao.java

package sh.shop.dao;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.ArrayListHandler;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import sh.shop.domain.Product;
import sh.shop.utils.DataSourceUtils;

public class ProductDao {
    // 
    public List<Product> listAll() throws SQLException {
        String sql = "select * from products";
        QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
        List<Product> list = runner.query(sql, new BeanListHandler<Product>(Product.class));
        return list;
    }
    
    //
    public void addProduct(Product p) throws SQLException {

        String sql = "insert into products values(?,?,?,?,?,?,?)";
        QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
        runner.update(sql, p.getId(), p.getName(), p.getPrice(),
                null, p.getImgurl(), p.getDescription());
    }
}

list.jsp

<tbody>
<c:forEach items="${list}" var="p">
    <tr class="text-c va-m">
        <td><input name="" type="checkbox" value=""></td>
        <td>${p.id }</td>
        <td><a onClick="" href="javascript：;"><img width="60" class="product-thumb" src=""></a></td>
        <td class="text-l"><a style="text-decoration:none" onClick="" href="javascript：;">${p.name }</a></td>
        <td class="text-l">${p.description }</td>
        <td>${p.price }</td>
        <td>${p.category }</td>
        <td class="td-manage"><a style="text-decoration:none" class="ml-5" onClick="product_edit("","product-add.html","10001")" href="javascript：;" title=""><i class="Hui-iconfont"></i></a> <a style="text-decoration:none" class="ml-5" onClick="product_del(this,"10001")" href="javascript：;" title=""><i class="Hui-iconfont"></i></a></td>
    </tr>
</c:forEach>
</tbody>