springboot中如何映射实体类对象？

Question

This is my entity class , which I am using to save the details of customer along with the purchase detail and product purchased and payment module , Its finely saving in DB but while retrieving getting result as null .

@Entity
@Table(name = "productpurchasedata")
public class Test {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int customerid;
    @ManyToOne(cascade = { CascadeType.ALL })
    @JoinColumn(name = "customerid", insertable = false, updatable = false)
    private CustomerProductSave customerProductSave;
    @ManyToOne(cascade = { CascadeType.ALL })
    @JoinColumn(name = "customerid", insertable = false, updatable = false)
    private PurchaseDetails purchasedetails;
    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name = "customerid")
    private List<ProductPurchased> productpurchased;
    @ManyToOne(cascade = { CascadeType.ALL })
    @JoinColumn(name = "customerid", insertable = false, updatable = false)
    private PaymentHistory paymenthistory;

Here I am able to save the data which result in something like this :-

{
    "customerid": 1,
    "customerProductSave": {
        "customerids": 2,
        "name": "nitesh",
        "mailid": "niteshbhushan95@gmail.com",
        "address": "hyd",
        "city": "telanagana",
        "state": "telanagana",
        "postalcode": "847226",
        "mobileno": 6300769631
    },
    "purchasedetails": {
        "purchasedate": "22-07-2021",
        "modeofpayment": "paytm",
        "emiapplicable": false,
        "totalamount": 21000,
        "purchaseId": 4
    },
    "productpurchased": [
        {
            "purchaseid": 5,
            "purchaseamount": 2000,
            "purchasedproductid": 1,
            "productquantity": 0
        },
        {
            "purchaseid": 6,
            "purchaseamount": 2000,
            "purchasedproductid": 1,
            "productquantity": 0
        }
    ],
    "paymenthistory": {
        "transactionid": 3,
        "paymentstatus": "paid"
    }
}

Now when I am trying to retrieve the data by customerid it is not accepting , it giving message as null , I am not pretty much may be some mistake in mapping

Answer 1

尝试使用 fetch = FetchType.EAGER 而不是 fetch = FetchType.LAZY 在所有映射购买细节和产品购买和支付模块