Spring jpa休眠插入OneToMany

Question

我正在尝试在表 (OneToMany) 中插入数据。我有两张桌子（好，类别）。

    @Entity
    @Table(name = "goods")
    public class Good implements Serializable {

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "category_id")
    private Category category;

    @JsonBackReference
    public Category getCategory() {
        return category;
    }
    //getters,setters is ommited

还有一个：

    @Entity
    @Table(name = "category_of_products")
    public class Category implements Serializable {

    @OneToMany(mappedBy = "category", fetch = FetchType.LAZY, cascade = {
            CascadeType.PERSIST, CascadeType.REFRESH })
    private List<Good> goods;

    @JsonManagedReference
    public List<Good> getGoods() {
        return goods;
    }
    //getter, setters ommited

例如，在类别中（id=1），我尝试创建与该类别相关的产品。

@RequestMapping(value = CATEGORIES_ID_GOODS_ADD_DO, method = RequestMethod.POST)
        public String addGoodAction(@PathVariable("id") Integer id,
                @Valid Good good, BindingResult bindingResult, Model model) {
            goodValidator.validate(good, bindingResult);
            if (bindingResult.hasErrors()) {
                return JspNamesUtil.GOODS_BY_CATEGORY;
            } else {
                RestTemplate restTemplate = new RestTemplate();
                Category category = restTemplate.getForObject(
                        "http://localhost:8080/InternetShop/rest/category/" + id,
                        Category.class);            //here i have category by id

                // good.setCategory(category);
                // goodManager.saveOrUpdate(good);  doesn't insert anything

                category.getGoods().add(good);      //get all products from category and add new product
                model.addAttribute("good", good);
                categoryManager.saveOrUpdate(category); // doesn't insert anything
            }
            return JspNamesUtil.GOODS_BY_CATEGORY;
        }

他们不会在我的表中插入任何内容。

Hibernate: select category0_.id as id1_0_0_, category0_.name as name2_0_0_ from category_of_products category0_ where category0_.id=?
Hibernate: select goods0_.category_id as category7_0_0_, goods0_.id as id1_1_0_, goods0_.id as id1_1_1_, goods0_.category_id as category7_1_1_, goods0_.description as descript2_1_1_, goods0_.name as name3_1_1_, goods0_.price as price4_1_1_, goods0_.quantity as quantity5_1_1_, goods0_.short_description as short_de6_1_1_ from goods goods0_ where goods0_.category_id=?

方法持久化也不起作用（分离实体异常）

DAO 示例

public Category saveOrUpdate(Category category) {
        if (category != null) {
            em.merge(category);
        }
        return category;
        }
        public void add(Category category) {
           em.persist(category);
        }

请给我一个提示，我做错了什么？

Answer 1

这可能是一个可以根据您的测试而发展的测试解决方案：

有两件事要做：

1. 将您的CascadeType.PERSIST 更改为CascadeType.CASCADE_ALL以不必处理级联问题（一旦此解决方案有效，您可以回滚）。
2. 在Category 类中添加一个addGood(Good good) 并在Good 类中添加（如果它不存在）Category 的设置器。您必须管理将Good 连接到Category 并将Category 连接回Good 的双向关系。

addGood 方法将是这样的：

public void addGood(Good good) {
 this.goods.add(good);
 good.setCategory(this);
}