java - 无法删除 spring-hibernate 中的实体

Question

我使用的是 hibernate 版本 4.3.11.Final。当我尝试从jsp页面删除产品时，它会进入 Controller 并完全执行。但是，它在控制台上显示此消息:org.hibernate.event.internal.DefaultDeleteEventListener deleteTransientEntity信息:HHH000114:在删除处理中处理临时实体

有人有解决办法吗？

这是我的 Controller :

@RequestMapping("/deleteProduct")
    public ModelAndView delete(@ModelAttribute("product") Product product, BindingResult result)
    {
        System.out.println("In delete");
        productDAO.delete(product);
        System.out.println("Product Successfully deleted");
        return new ModelAndView("AdminProduct");
    }

这是我的 JSP:

<c:forEach items="${products}" var="product">
                <tr
                    style="background-color: white; color: black; text-align: center;"
                    height="30px">
                    <td><c:out value="${product.p_id}" /></td>
                    <td><c:out value="${product.p_name}" /></td>
                    <td><c:out value="${product.p_desc}" /></td>
                    <td><c:out value="${product.price}" /></td>
                    <td><form:form action="deleteProduct" modelAttribute="product">
                            <input type="submit" value="Delete" />
                        </form:form></td>
                    <td><form:form action="editProduct" modelAttribute="product">
                            <input type="submit" value="Edit" />
                        </form:form></td>
                </tr>
            </c:forEach>

而且，这是我针对该实体的 DAOImpl 类:

package com.niit.shoppingcart.dao;

import java.util.List;

import javax.transaction.Transactional;

import org.hibernate.Query;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.niit.shoppingcart.model.Product;

@Repository(value = "productDAO")
public class ProductDAOImpl implements ProductDAO {

    @Autowired
    private SessionFactory sessionFactory;

    @Transactional
    public boolean save(Product product) {
        try {
            sessionFactory.getCurrentSession().save(product);
            return true;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return false;
        }
    }

    @Transactional
    public boolean update(Product product) {
        try {
            sessionFactory.getCurrentSession().update(product);
            return true;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return false;
        }
    }

    @Transactional
    public boolean delete(Product product) {
        try {
            sessionFactory.getCurrentSession().delete(product);
            return true;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return false;
        }
    }

    @Transactional
    public Product get(String id) {
        String hql = "from Product where id = " + " ' " + id + " ' ";
        Query query = sessionFactory.getCurrentSession().createQuery(hql);
        @SuppressWarnings("unchecked")
        List<Product> plist = (List<Product>) query.list();

        if (plist == null || plist.isEmpty()) {
            return null;
        } else {
            return plist.get(0);
        }
    }

    @SuppressWarnings("unchecked")
    @Transactional
    public List<Product> listAll() {
        String hql = "from Product";
        Query query = sessionFactory.getCurrentSession().createQuery(hql);
        return query.list();
    }

}

这是实体类:

package com.niit.shoppingcart.model;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

import org.springframework.stereotype.Component;

@Entity
@Table(name = "PRODUCT")
@Component
public class Product {

    @Id
    private String p_id;
    private String p_name;
    private String p_desc;
    private int price;

    public String getP_id() {
        return p_id;
    }

    public void setP_id(String p_id) {
        this.p_id = p_id;
    }

    public String getP_name() {
        return p_name;
    }

    public void setP_name(String p_name) {
        this.p_name = p_name;
    }

    public String getP_desc() {
        return p_desc;
    }

    public void setP_desc(String p_desc) {
        this.p_desc = p_desc;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }
}

Answer 1

在 Controller 中，您获得一个Product Object产品，并且该产品不受Hibernate的控制。因此，如果您想删除带有产品实体的记录，您应该在删除之前从数据库中选择它。就像下面这样，

Product p = productDAO.get(product.getId());
productDAO.delete(p);

删除记录的更好方法是在 ProductDAO 中添加一个方法，例如 deleteById(String id) 并使用参数 product.getId() 调用它;