Question

我搜索了很多，仍然没有找到任何解决方案因此在这里发布了一个问题..

我正在使用lombok开发多对多关系示例。我只想为四个中的两个字段创建参数构造函数。我们怎么做到这一点？

@Data
@Entity
@Table(name = "stock")
public class Stock implements Serializable{

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "STOCK_ID", unique = true, nullable = false)
    private Integer stockId;

    @Column(name = "STOCK_CODE", unique = true, nullable = false, length = 10)
    private String stockCode;

    @Column(name = "STOCK_NAME", unique = true, nullable = false, length = 20)
    private String stockName;

    @ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinTable(name = "stock_category", joinColumns = {
        @JoinColumn(name = "STOCK_ID", nullable = false, updatable = false)},
        inverseJoinColumns = {@JoinColumn(name = "CATEGORY_ID", nullable = false, updatable = false)})
    private Set<Category> categories = new HashSet<Category>(0);
}

分类

@Data
@RequiredArgsConstructor(staticName = "of")
@Entity
@Table(name = "category")
public class Category {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "CATEGORY_ID", unique = true, nullable = false)
    private Integer categoryId;

    @Column(name = "NAME", nullable = false, length = 10)
    @NonNull
    private String name;

    @Column(name = "[DESC]", nullable = false)
    @NonNull
    private String desc;

    @ManyToMany(fetch = FetchType.LAZY, mappedBy = "categories")
    private Set<Stock> stocks = new HashSet<Stock>(0);
}

App.java

为什么我无法设置限制字段构造函数

public class App {
    public static void main(String[] args) {
        System.out.println("Hello World!");
        Session session = HibernateUtil.getSessionFactory().openSession();

        session.beginTransaction();

        Stock stock = new Stock();
        stock.setStockCode("7052");
        stock.setStockName("PADINI");

        Category category1 = new Category("CONSUMER", "CONSUMER COMPANY");
        Category category2 = new Category("INVESTMENT", "INVESTMENT COMPANY");

        Set<Category> categories = new HashSet<Category>();
        categories.add(category1);
        categories.add(category2);

        stock.setCategories(categories);

        session.save(stock);

        session.getTransaction().commit();
        System.out.println("Done");
    }
}

Answer 1

原因是

如果staticName设置，生成的构造函数将是私有的，另外还有 static'constructor'是使用相同的参数列表生成的包装真正的构造函数。

请不要忘记@NoArgsConstructor，因为Hibernate需要它。

构造函数Category（String，String）不可见 - 使用lombok为某些字段创建构造函数？

1 个答案: