InvoiceInfo应为联接表，根据您要求使用@OneToMany，@ManyToOne注解定义实体Product和Invoice关系

您必须使用一组注解来建立实体之间的关系，例如：@ManyToOne、@OneToMany、@ManyToMany或@OneToOne ...以及其他注解（如果需要）。
在您的情况下，我不确定是否需要InvoiceInfo表，因为Invoice表已经可以（或应该）包含产品列表。
我建议您建立以下关系：

产品名称

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

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;
    @Column(name = "family_id")
    private long familyId;   
    @Column(name = "product_name")
    private String productName;
    @Column(name = "product_category")
    private String productCategory;
    @Column(name = "product_quantity") 
    private int productQuantity;
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "invoice_id", referencedColumnName = "id")
    private Invoice invoice;
    //getters and setters
}

发票

@Entity
@Table(name = "invoice")
public class Invoice {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "invoice_id")
    private Long id;
    @Column(name = "provider_id")
    private Long providerId;
    @Column(name = "total")
    private int invoiceTotal;
    @Column(name = "date")
    private Date invoiceDate;
    @OneToMany(mappedBy = "product")
    private List<Product> products;
    //getters and setters
}

由于您的表InvoiceInfo已不存在，您只需将数据插入两个表中，如下所示：

Invoice invoice = invoiceRepository.save(invoice);
Product product = new Product();
// Set the other properties
product.setInvoice(invoice);
productRepository.save(product);