java - JAX-RS JSON 编码后缺少子对象

Question

我使用 Glassfish、EclipseLink 和 JAX-RS 来提供通过 AngularJS/AJAX 从网站调用的 REST 服务。我返回一个 SalesOrder 类型的 JSON 对象，该对象具有一个名为 lineItems 类型的属性，该属性在属性属性和 List<SalesOrderLine> 方法上都用 @OneToMany 注释。

我已成功调用 REST 资源并返回一个表示父 getLineItems() 对象的 JSON 对象，但是，即使服务器端日志指示响应对象具有一个带有 (2) SalesOrder 对象的 SalesOrder 实体，客户端上的 JSON 对象/浏览器端缺少对子 lineItems 列表或其内容的任何引用。

Glassfish log contents:
2015-05-03T18:38:30.480-0600|Info: SalesOrder found with UID: 51
2015-05-03T18:38:30.480-0600|Info: Number of line items sent back to the REST service with the order is: 2
2015-05-03T18:38:30.480-0600|Info: Item Quantity is: 10
2015-05-03T18:38:30.480-0600|Info: Item Quantity is: 5
2015-05-03T18:38:30.480-0600|Info: Response status: 200
2015-05-03T18:38:30.480-0600|Info: Response status info: OK
2015-05-03T18:38:30.480-0600|Info: Response class: class org.glassfish.jersey.message.internal.OutboundJaxrsResponse
2015-05-03T18:38:30.480-0600|Info: Response length: -1
2015-05-03T18:38:30.480-0600|Info: Response media type: application/json
2015-05-03T18:38:30.480-0600|Info: Response entity: business.salesOrderMgmt.entity.SalesOrder@2a461205
2015-05-03T18:38:30.480-0600|Info: Response entity number of line items: 2
2015-05-03T18:38:30.481-0600|Info: Response is: OutboundJaxrsResponse{status=200, reason=OK, hasEntity=true, closed=false, buffered=false}

客户端/浏览器端的 JSON 对象:

{
    "salesOrderUid": 51,
    "orderNumber": "1428002042749",
    "billToCity": "Golden",
    "billToFirstName": "Duke",
    "billToLastName": "Developer",
    "billToState": "CO",
    "billToStreetName": "Technology Row",
    "billToStreetNumber": "12345",
    "billToUnitNumber": null,
    "billToZipCode": 80401,
    "creditCardCsv": 123,
    "creditCardExpirationDate": 1483254001000,
    "creditCardNumber": "123456789012",
    "creditCardType": "Visa",
    "emailAddress": "ddeveloper@techexpertconsulting.com",
    "nameOnCreditCard": "Duke Developer",
    "salesOrderDate": 1428002043000,
    "salesOrderStatus": "New",
    "shipToCity": "Golden",
    "shipToState": "CO",
    "shipToStreetName": "Technology Row",
    "shipToStreetNumber": "12345",
    "shipToUnitNumber": null,
    "shipToZipCode": 80401,
    "promoCode": "Test",
    "discount": 5,
    "salesTax": 3.2500000000000001804112415015879378188401460647583007812500,
    "shipping": 10,
    "total": 78.2500000000000001804112415015879378188401460647583007812500
}

因此，响应对象的编码似乎正在丢弃子对象。

有人见过这个问题并知道如何解决吗？

Answer 1

从你的回答看here ，您已经发现了使用 @XmlTransient 来避免循环依赖。这样做的问题是，它在编码/解码时完全忽略该属性。

那么我们该如何解决这个问题呢？鉴于您如何使用 Glassfish(默认情况下使用 MOXy 进行 JSON 处理)，您可以简单地使用 @XmlID和 @XmlIDREF 。以下是我用来测试的内容

public class SalesOrder {

    private String id;
    private List<SalesOrderLine> salesOrderItems;

    @XmlID
    public String getId() { return id; }
    ...
}

public class SalesOrderLine {
    private String id;
    private String item;
    private SalesOrder salesOrder;

    @XmlIDREF
    public SalesOrder getSalesOrder() { return salesOrder; }
    ...
}

@GET
@Produces(MediaType.APPLICATION_JSON)
public Response getSalesOrder() {
    SalesOrder salesOrder = new SalesOrder("12345");

    List<SalesOrderLine> salesOrderItems = new ArrayList<>();
    SalesOrderLine line = new SalesOrderLine("123", "item1", salesOrder);
    salesOrderItems.add(line);
    line = new SalesOrderLine("124", "item2", salesOrder);
    salesOrderItems.add(line);

    salesOrder.setSalesOrderItems(salesOrderItems);

    return Response.ok(salesOrder).build();
}

而且效果很好。 SalesOrder id 用作 SalesOrderLine 对象中的 salesOrder 值。如果没有这些注释，我会从 MOXy 收到循环依赖错误。

注意:根据我的测试，如果使用了 JAXB 注释支持模块，该解决方案也适用于 Jackson。