即使使用FetchType.EAGER，也会出现hibernate lazyinitializationexception

Question

Cart.java

    @Entity
    @Table(name = "cart")
    public class Cart {

        @Id
        @GeneratedValue
        @Column(name = "cart_id")   
        private int id;
        @Column(name = "cart_status")   
        private int status;

        @ManyToOne(optional = false)
        @JoinColumn(name = "user_id")
        private User user;


        @OneToMany(mappedBy = "cart",fetch=FetchType.EAGER, cascade = CascadeType.ALL)
        private List<OrderDetails> orderDetails ;

        @OneToMany(mappedBy = "cart", cascade = CascadeType.ALL)
        private List<Transactions> transactions ;

}

CartController.java

@RequestMapping("/displaycart")
public String displayCart(Map<String, Object> map, Principal principal) {
    String name = null;
    if (principal != null) {
        name = principal.getName();
    }
    User user = userService.findUserByName(name);

    Cart isCartExisting = cartService.isCartExisting(user.getId());
    List<OrderDetails> orderDetails=isCartExisting.getOrderDetails();
    map.put("orderDetails", orderDetails);
         for(OrderDetails o:orderDetails)
         {
             System.out.println(o.getProducts());
         }
    return "redirect:/productlist";
}

cartserviceimpl.java

@Service
public class CartServiceImpl implements CartService {

    @Autowired
    private CartDao cartDao;
    @Autowired
    private OrderDetailsService orderDetailsService;
    @Override
    @Transactional
    public Integer saveCart(User user, int productid) {
        Product product = new Product(productid);

        Cart cart = new Cart();
        cart.setUser(user);
        cart.setStatus(0);

        OrderDetails orderDetails1 = new OrderDetails();
        orderDetails1.setUser(cart.getUser());
        orderDetails1.setProducts(product);
        orderDetails1.setCart(cart);

        List<OrderDetails> listOfOrders = new ArrayList<OrderDetails>();
        listOfOrders.add(orderDetails1);

        cart.setOrderDetails(listOfOrders);

        int result = cartDao.saveCart(cart);
        System.out.println(result);
        return result;
    }

    @Override
    @Transactional
    public int saveCart(User user, int cartid, int productid) {
        Cart cart = cartDao.getCart(cartid);
        //is order details existing with given product id?
        OrderDetails isItemExisting = orderDetailsService.isItemExisting(productid);
        if(isItemExisting!=null){
            //add in existing
            isItemExisting.setQuantity(isItemExisting.getQuantity()+1);

           List<OrderDetails> listOfOrders = new ArrayList<OrderDetails>();
            listOfOrders.add(isItemExisting);

            cart.setOrderDetails(listOfOrders);

            int result = cartDao.saveCart(cart);
            System.out.println(result);
            return result;
        }else{
            //new 
            Product product = new Product(productid,1);

            OrderDetails orderDetails1 = new OrderDetails();
            orderDetails1.setUser(cart.getUser());
            orderDetails1.setProducts(product);
            orderDetails1.setCart(cart);

            List<OrderDetails> listOfOrders = new ArrayList<OrderDetails>();
            listOfOrders.add(orderDetails1);

            cart.setOrderDetails(listOfOrders);

            int result = cartDao.saveCart(cart);
            System.out.println(result);
            return result;
        }

    }

    @Override
    @Transactional(readOnly = true)
    public Cart isCartExisting(int userID) {
        return cartDao.isCartExisting(userID);
    }

}

orderdetails.java

@Entity
@Table(name = "order_details")

    public class OrderDetails {

        @Id
        @GeneratedValue
        @Column(name = "orderdetails_id")   
        private int id;

        @Column(name = "product_quantity")  
        private int quantity;

        @ManyToOne(optional = false)
        @JoinColumn(name = "product_id")
        private Product products;

        @ManyToOne(optional = false)
        @JoinColumn(name = "user_id")
        User user;

        @ManyToOne(optional = false, cascade = CascadeType.ALL)
        @JoinColumn(name = "cart_id")
        Cart cart;
}

product.java

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

    @Id
    @GeneratedValue
    @Column(name = "product_id")
    private int id;

    @Column(name = "product_name")
    private String name;

    @Column(name = "product_price")
    private int price;

    public int getPrice() {
        return price;
    }

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

    @OneToMany(mappedBy = "products", cascade = CascadeType.ALL)
    private List<OrderDetails> orderDetails;
}

cartdaoimpl.java

public class CartDaoImpl implements CartDao {
    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public Integer saveCart(Cart cart) {

        return (Integer) getSession().save(cart);
    }

    @Override
    public Cart isCartExisting(int userID) {

        Criteria c = getSession().createCriteria(Cart.class);
        c.add(Restrictions.eq("user", new User(userID))).add(
                Restrictions.eq("status", new Integer(0)));
        return (Cart) c.uniqueResult();
    }

    private Session getSession() {
        Session sess = getSessionFactory().getCurrentSession();
        if (sess == null) {
            sess = getSessionFactory().openSession();
        }
        return sess;
    }

    private SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    @Override
    public Cart getCart(int id) {
        Cart cart = (Cart) getSession().get(Cart.class, new Integer(id));

        return cart;
    }
}

我得到了这个受欢迎的

HTTP Status 500 - Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.addtocart.dto.Cart.orderDetails, could not initialize proxy - no Session

type Exception report

message Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.addtocart.dto.Cart.orderDetails, could not initialize proxy - no Session

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.addtocart.dto.Cart.orderDetails, could not initialize proxy - no Session
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:973)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:108)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)
root cause

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.addtocart.dto.Cart.orderDetails, could not initialize proxy - no Session
    org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:572)
    org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:212)
    org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:551)
    org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:140)
    org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:294)
    com.addtocart.controller.CartController.displayCart(CartController.java:57)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:497)
    org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:690)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:108)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)

，我在cart.java上经历了许多解决方案，例如fetch =FetchType.EAGER和@lazy(false)，但是无法解决这个问题，可以解释为什么我会得到即使我正在急切地使用{获取所有值{1}}。任何人都可以通过任何方式解决这个问题。

git hub link- https://github.com/emosrb/AddToCart