运行时GSON对象类型转换

Question

我有一个模板对象类型ExternalActionReqBean，该对象具有可以通过指示操作字段设置的任何类的对象

可以说，如果action =“ FROZEN”，ExternalActionReqBean-> payload将使用ExternalActionFrozenReqBean类类型，如果使用action =“ UNFROZEN” ExternalActionUnFrozenReqBean类类型。

如果有效载荷如下所示，那么实现此目标的最佳实践是什么？

{ “txnID”： “TXN”， “动作”： “冻结”， “资源”： “PNSENDER”， “有效载荷”：{“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

我更改了ExternalActionReqBean类签名，将其类型转换为Generic，然后使用TypeToken如下。

@Data
@AllArgsConstructor
public class ExternalActionReqBean<T> {

   private String txnID;
   private String action;
   private String resource;
   private T payload;

}

码：

 if ("FROZEN".equals(externalActionReqBean.getAction())) {
  Type complexType = new TypeToken<ExternalActionReqBean<ExternalActionFrozenReqBean>>() {}.getType();
  ExternalActionReqBean<ExternalActionFrozenReqBean> result = GSON.fromJson(payload, complexType);

}

感谢您的https://futurestud.io/tutorials/gson-advanced-generics ，您可以在“反序列化泛型”下找到更多信息