not-null属性引用的是null还是瞬态值？

Question

我是春季新人。我有一个名为SampleStore的项目。在我的项目中创建的一些实体，例如User，UserRole，Product，Orders，CartItem和....，但是我有问题。当我尝试添加新的用户应用程序时，它不会出现错误，并且在databse中插入了新记录。但是当我尝试插入新订单时，我会收到错误消息。

User.java

@Entity
@Table(name = "users")
public class User implements Serializable, UserDetails {

    private static final long serialVersionUID = -8245107356306518473L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false)
    private Long id;

    @Column(name = "username", nullable = false, unique = true, length = 50)
    private String username;

    @Column(name = "password", nullable = false, length = 60)
    private String password;

    @Column(name = "enabled", nullable = true, columnDefinition = "tinyint(1) default 1")
    private boolean enabled;

    @Column(name = "expired", nullable = true, columnDefinition = "tinyint(1) default 1")
    private boolean accountNonExpired;

    @Column(name = "locked", nullable = true, columnDefinition = "tinyint(1) default 1")
    private boolean accountNonLocked;

    @Column(name = "credential", nullable = true, columnDefinition = "tinyint(1) default 1")
    private boolean credentialsNonExpired;

    @Column(name = "gender", nullable = true)
    private char gender;

    @Column(name = "address", nullable = true)
    private String address;

    @Column(name = "phonenumber", nullable = true)
    private String phoneNumber;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "user")
    private Set<UserRole> userRoles = new HashSet<UserRole>(0);

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "user")
    private List<Comment> comments = new ArrayList<Comment>();

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "user")
    private List<Orders> orders = new ArrayList<Orders>();

    public User() {
    }

    public User(String username, String password, boolean enabled) {
        this.username = username;
        this.password = password;
        this.enabled = enabled;
    }

    public User(String username, String password, boolean enabled, Set<UserRole> userRoles) {
        this.username = username;
        this.password = password;
        this.enabled = enabled;
        this.userRoles = userRoles;
    }

    public User(String username, String password, boolean enabled, boolean accountNonExpired,
            boolean credentialsNonExpired, boolean accountNonLocked, Set<UserRole> authorities) {

        this.username = username;
        this.password = password;
        this.enabled = enabled;
        this.accountNonExpired = accountNonExpired;
        this.credentialsNonExpired = credentialsNonExpired;
        this.accountNonLocked = accountNonLocked;
        this.userRoles = authorities;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public boolean isEnabled() {
        return enabled;
    }

    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public Set<UserRole> getUserRoles() {
        return userRoles;
    }

    public void setUserRoles(Set<UserRole> userRoles) {
        this.userRoles = userRoles;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public char getGender() {
        return gender;
    }

    public void setGender(char gender) {
        this.gender = gender;
    }

    public List<Comment> getComments() {
        return comments;
    }

    public void setComments(List<Comment> comments) {
        this.comments = comments;
    }

    public List<Orders> getOrders() {
        return orders;
    }

    public void setOrders(List<Orders> orders) {
        this.orders = orders;
    }

    @Override
    public String toString() {
        return "User [id=" + id + ", username=" + username + ", password=" + password + ", enabled=" + enabled
                + ", gender=" + gender + ", address=" + address + ", phoneNumber=" + phoneNumber + ", userRoles="
                + userRoles + "]";
    }

    public Collection<? extends GrantedAuthority> getAuthorities() {

        Set<GrantedAuthority> setAuths = new HashSet<GrantedAuthority>();

        for (UserRole userRole : userRoles) {
            setAuths.add(new SimpleGrantedAuthority(userRole.getRole()));
        }
        List<GrantedAuthority> result = new ArrayList<GrantedAuthority>(setAuths);

        return result;
    }

    public boolean isAccountNonExpired() {
        return accountNonExpired;
    }

    public boolean isAccountNonLocked() {
        return accountNonLocked;
    }

    public boolean isCredentialsNonExpired() {
        return credentialsNonExpired;
    }

    public void setAccountNonExpired(boolean accountNonExpired) {
        this.accountNonExpired = accountNonExpired;
    }

    public void setAccountNonLocked(boolean accountNonLocked) {
        this.accountNonLocked = accountNonLocked;
    }

    public void setCredentialsNonExpired(boolean credentialsNonExpired) {
        this.credentialsNonExpired = credentialsNonExpired;
    }

}

UserRole.java

@Entity
@Table(name = "user_roles", uniqueConstraints = @UniqueConstraint(columnNames = { "username", "role" }))
public class UserRole {

    private Integer userRoleId;
    private User user;
    private String role;

    public UserRole() {
    }

    public UserRole(User user, String role) {
        this.user = user;
        this.role = role;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "user_role_id", unique = true, nullable = false)
    public Integer getUserRoleId() {
        return this.userRoleId;
    }

    public void setUserRoleId(Integer userRoleId) {
        this.userRoleId = userRoleId;
    }

    @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name = "username", nullable = false)
    public User getUser() {
        return this.user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    @Column(name = "role", nullable = false, length = 45)
    public String getRole() {
        return this.role;
    }

    public void setRole(String role) {
        this.role = role;
    }

}

Orders.java

@Entity
@Table(name = "orders")
public class Orders implements Serializable {

    private static final long serialVersionUID = -3672662224925418969L;

    @Id
    @Column(name = "ord_id", nullable = false)
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @DateTimeFormat(pattern = "yyyy-mm-dd")
    @Column(name = "orderDate", nullable = false)
    private Date orderDate;

    @DateTimeFormat(pattern = "yyyy-mm-dd")
    @Column(name = "delivery", nullable = false)
    private Date deliveryDate;

    @Column(name = "success", nullable = true, columnDefinition = "tinyint(1) default 0")
    private boolean success;

    @Column(name = "cancel", nullable = true, columnDefinition = "tinyint(1) default 0")
    private boolean canceled;

    @Column(name = "cause", nullable = true)
    private String cancelCause;

    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "order")
    private List<CartItem> items = new ArrayList<CartItem>();

    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name="username",nullable=false)
    private User user;

    public Orders() {
    }

    public Orders(Date deliveryDate, List<CartItem> items, User user) {
        this.orderDate = new Date();
        this.deliveryDate = deliveryDate;
        this.items = items;
        this.user = user;
    }

    public Orders(List<CartItem> items, User user) {
        this.orderDate = new Date();
        this.items = items;
        this.user = user;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Date getOrderDate() {
        return orderDate;
    }

    public void setOrderDate(Date orderDate) {
        this.orderDate = orderDate;
    }

    public Date getDeliveryDate() {
        return deliveryDate;
    }

    public void setDeliveryDate(Date deliveryDate) {
        this.deliveryDate = deliveryDate;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public boolean isSuccess() {
        return success;
    }

    public void setSuccess(boolean success) {
        this.success = success;
    }

    public boolean isCanceled() {
        return canceled;
    }

    public void setCanceled(boolean canceled) {
        this.canceled = canceled;
    }

    public String getCancelCause() {
        return cancelCause;
    }

    public void setCancelCause(String cancelCause) {
        this.cancelCause = cancelCause;
    }

    public List<CartItem> getItems() {
        return items;
    }

    public void setItems(List<CartItem> items) {
        this.items = items;
    }
}

CartItem.java

@Entity
@Table(name = "saleitems", uniqueConstraints = {})
public class CartItem implements Serializable {

    private static final long serialVersionUID = 7968604053015663078L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(nullable = false)
    private Long id;

    @Column(name = "prd_id", nullable = false)
    private Product product;

    @Column(name = "quantity", nullable = false, columnDefinition = "int(11) default 1")
    private Integer quantity;

    @Column(name = "totalprice", nullable = false)
    private BigDecimal totalprice;

    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "orderid", nullable = false)
    private Orders order;

    public CartItem(Product product, Integer quantity) {
        this.product = product;
        this.quantity = quantity;
        setTotalprice();
    }

    public CartItem() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Product getProduct() {
        return product;
    }

    public void setProduct(Product product) {
        this.product = product;
    }

    public Integer getQuantity() {
        return quantity;
    }

    public void setQuantity(Integer quantity) {
        this.quantity = quantity;
    }

    public BigDecimal getTotalprice() {
        return totalprice;
    }

    public void setTotalprice() {
        this.totalprice = getProduct().getPrice().multiply(new BigDecimal(getQuantity()));
    }

    public Orders getOrder() {
        return order;
    }

    public void setOrder(Orders order) {
        this.order = order;
    }

}

这是我的控制器代码的一部分，该用户用于保存新用户和保存新订单。

@RequestMapping(value = "/saveuser", method = RequestMethod.POST)
    public ModelAndView saveNewUser(@ModelAttribute User user) {

        ModelAndView model = new ModelAndView();
        user.setEnabled(true);
        user.setAccountNonExpired(true);
        user.setAccountNonLocked(true);
        user.setCredentialsNonExpired(true);
        UserRole role = new UserRole(user, "ROLE_USER");
        Set<UserRole> roles = new HashSet<UserRole>();
        roles.add(role);
        user.setUserRoles(roles);

        String result = userService.addUser(user);

        if (!result.toLowerCase().startsWith("error")) {
            model.setViewName("loginForm");
        } else {
            model.setViewName("newuser");
            model.addObject("error", result);
        }
        return model;
    }
@SuppressWarnings("unchecked")
    @RequestMapping(value = "/store/addorder", method = RequestMethod.GET)
    public ModelAndView addOrder(HttpSession session) {

        ModelAndView model = new ModelAndView();

        // create list of products that we have to add in orders
        System.err.println("item get to retrieving---------------");
        List<CartItem> items = (List<CartItem>) session.getAttribute("cart");
        for (CartItem cartItem : items) {
            System.err.println(cartItem.getProduct());
        }

        // find user by username to set orders userinfo
        System.err.println("user information get to retriving---------------");
        String username = SecurityContextHolder.getContext().getAuthentication().getName();
        User user = userService.findByUsername(username);
        System.err.println(user);

        // new order generated and setter methods invoke
        System.err.println("new order generated-------------------");
        Orders order = new Orders(items, user);
        Date d = new Date();
        Date delivery = StoreUtils.deliveryDate(d, 3);
        order.setOrderDate(d);
        order.setDeliveryDate(delivery);
        order.setUser(user);
        order.setItems(items);
        String addOrders = orderService.addOrders(order);
        System.err.println("new order add status " + addOrders + "-------------");
        System.err.println(order);
        // change product quantity after adding new order
        for (int i = 0; i < items.size(); i++) {
            Integer qSale = items.get(i).getQuantity() * (-1);
            productService.rechargeProduct(items.get(i).getProduct(), qSale);
        }

        if (!addOrders.toLowerCase().contains("error")) {
            model.setViewName("successorder");
            model.addObject("order", order);
            model.addObject("message", addOrders);
            session.setAttribute("cart", null);
        } else {
            session.setAttribute("error", addOrders);
            model.setViewName("redirect:/addtocartlist");
        }
        return model;
    }

最后，这是我在dao类中保存用户和订单的代码。

UserDaoImpl.java

public String addUser(User user) {
        String result = "";
        String pass = encoder.encode(user.getPassword());
        user.setPassword(pass);

        try {
            session().save(user);
            session().flush();
            result = "success";
        } catch (Exception e) {
            if (e.getCause().getMessage().toLowerCase().contains("duplicate"))
                result = "error :user is already joined to store!";
            else
                result = "error :" + e.getCause().getMessage();
        }

        return result;
    }

OrderDaoImpl.java

public String addOrders(Orders orders) {
        String result = "";

        try {
            session().save(orders);
            result = "success";

        } catch (Exception e) {
            if (e.getCause() != null)
                if (e.getCause().getMessage().toLowerCase().contains("duplicate"))
                    result = "error this  order already was exist";
                else
                    result = "error " + e.getCause().getMessage();
            else {
                result = "error " + e.getMessage();
            }

            System.err.println(result);
        } finally {
            session().clear();
        }
        return result;
    }

所有代码都相似，但是结果不同。当尝试添加新订单时，出现此异常：

  

非空属性引用一个空值或瞬态值：com.softup.store.entity.CartItem.order

Answer 1

设置关系的双方。在每个项目上调用setOrder（）。在用户setOrder（）上也是如此。