Spring JPA Hibernate插入OneToMany

Question

我正在嘗試在表（OneToMany）中插入數據。 我有兩個表（好，類別）。

    @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

還有一個：

    @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

比方說，在類別（id = 1）中，我嘗試創建與此類別相關的產品。

@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;
        }

他們沒有在我的桌子上插入任何東西。

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（分離實體異常）

DAO的例子

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

給我一個提示，我做錯了什么？

Answer 1

這可能是一個測試解決方案，可能會根據您的測試而變化：

有兩件事要做：

1. 將您的CascadeType.PERSIST更改為CascadeType.CASCADE_ALL不必處理級聯問題（一旦此解決方案起作用，您可以回滾此問題）。
2. 在Category類中添加一個addGood(Good good)並在Good類中為Category添加一個setter（如果尚不存在）。 你必須要管理雙directionnal關系配線Good於Category和布線回Category來Good 。

addGood方法將如下所示：

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