运行时 GSON 对象类型转换

Question

我有一个模板对象类型 ExternalActionReqBean 有一个对象，可以通过指示操作字段设置任何类

让我们说，如果 action="FROZEN" ， ExternalActionReqBean->payload 将使用 ExternalActionFrozenReqBean 类类型，如果 action="UNFROZEN" ExternalActionUnFrozenReqBean 类类型将被使用。

如果有效载荷如下所示，实现这一目标的最佳实践是什么？

{"txnID":"txn","action":"FROZEN","resource":"PNSENDER","payload":{"msisdn_list":["xxxx","xxx","xxx"]}}

ExternalActionReqBean externalActionReqBean = GSON.fromJson(payload, ExternalActionReqBean.class);

             if("FROZEN".equals(externalActionReqBean.getAction())){

               // externalActionFrozenReqBean = GSON.fromJson(externalActionReqBean.getPayload(),ExternalActionFrozenReqBean.class);

             }

@Data

@AllArgsConstructor

public class ExternalActionReqBean {

   private String txnID;

   private String action;

   private String resource;

   private Object payload;

}

@Data

public class ExternalActionFrozenReqBean {

   private List<String> msisdn_list;

}

@Data

public class ExternalActionUnFrozenReqBean {

   private String result;

}

Answer 1

我已经更改了 ExternalActionReqBean 类签名，它的类型被转换为通用，而不是使用 TypeToken 如下。@Data@AllArgsConstructorpublic class ExternalActionReqBean<T> {&nbsp; &nbsp;private String txnID;&nbsp; &nbsp;private String action;&nbsp; &nbsp;private String resource;&nbsp; &nbsp;private T payload;}代码：&nbsp;if ("FROZEN".equals(externalActionReqBean.getAction())) {&nbsp; Type complexType = new TypeToken<ExternalActionReqBean<ExternalActionFrozenReqBean>>() {}.getType();&nbsp; ExternalActionReqBean<ExternalActionFrozenReqBean> result = GSON.fromJson(payload, complexType);}感谢https://futurestud.io/tutorials/gson-advanced-generics，您可以在“泛型反序列化”下找到更多信息