尽管提到了属性，但出现无法识别的属性异常

Question

当我尝试读取传入的字符串消息时出现以下异常。

com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "EventID" (class org.json.JSONObject), not marked as ignorable (0 known properties: ])
 at [Source: {"MessageType": "EventSubscription","MessageData": {"EventID": ["ProximitySensorInRange", "ProximitySensorOutOfRange", "BarcodeBarcodeScanned", "RFIDRFIDScanned", "EXTERNALRFIDEXTERNALRFIDScanned", "ButtonsButtonPressed", "TestClientEvent", "ApplicationInteractionDetected", "ProductAdditionMethodBarcode", "ProductAdditionMethodRFID", "ProductAdditionMethodSearchAndAdd", "KohlsOfferKohlsCashUsed", "KohlsOfferGiftCardUsed", "KohlsOfferPromoCodesUsed", "SearchInputKeyedIn", "SearchInputVoice", "KubeUsageTime", "ProductAdditionMethodRecommendation", "ProductAdditionMethodUPCSearch"]}}; line: 1, column: 65] (through reference chain: com.kube.dataobjects.HostEventObject["MessageData"]->org.json.JSONObject["EventID"])
at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:51)
at com.fasterxml.jackson.databind.DeserializationContext.reportUnknownProperty(DeserializationContext.java:731)
at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:915)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1292)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1270)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:247)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:118)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:538)
at com.fasterxml.jackson.databind.deser.impl.FieldProperty.deserializeAndSet(FieldProperty.java:106)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:242)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:118)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3051)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2146)
at com.kube.websocketserver.KubeWebSocketServer.onMessage(KubeWebSocketServer.java:80)
at org.java_websocket.server.WebSocketServer.onWebsocketMessage(WebSocketServer.java:469)
at org.java_websocket.WebSocketImpl.decodeFrames(WebSocketImpl.java:368)
at org.java_websocket.WebSocketImpl.decode(WebSocketImpl.java:157)
at org.java_websocket.server.WebSocketServer$WebSocketWorker.run(WebSocketServer.java:657)

我是这样阅读邮件的。

hostEvent = mapper.readValue(message,HostEventObject.class);

这是我的 HostEventObject class。

public class HostEventObject {

public static final String MESSAGETYPE_SUBSCRIPTION = "eventsubscription";
public static final String MESSAGETYPE_EVENTFIRED = "eventfired";
public static final String MESSAGETYPE_FIREEVENT = "fireevent";

@JsonProperty("APIVersion")
private String APIVersion;

@JsonProperty("EventTime")
private String EventTime;

@JsonProperty("MessageType")
public String MessageType;

@JsonProperty("MessageData")
public JSONObject MessageData;
}

下面给出的是我的 JSON 字符串消息。

  {
   MessageType: "EventSubscription",
   MessageData: {
       EventID: ["test1","test2"]
   }
 }

为什么我会收到此异常？我读过类似的问题，但我没有拼写错误，也不能忽略这个属性。请指教

Answer 1

MessageData 的类型 JSONObject 没有名为 EventID 的字段。可能你想在这里放一个不同的 class？

这是你的 JSON

 MessageData: {
   EventID: ["test1","test2"]
 }

这需要消息数据的数据类型有一个 EventID 字段，它是某种列表/集合/数组或其他字符串集合。但是我们拥有的是 -

 @JsonProperty("MessageData")
 public JSONObject MessageData;

UPDATE 看起来 JSON 组织有一个 Jackson 模块：参见 https://github.com/FasterXML/jackson-datatype-json-org。要注册模块，您可以使用此：-

 ObjectMapper mapper = new ObjectMapper();
 mapper.registerModule(new JsonOrgModule());

Answer 2

您的 POJO 似乎缺少属性 EventID。您可以通过两种方式解决

在java POJO中添加属性。

把上面的代码忽略掉属性可以通过2种方式实现：

一个。标记 POJO 以忽略未知属性

@JsonIgnoreProperties(ignoreUnknown = true)

b。配置 ObjectMapper serializes/De-serializes POJO/json 如下：

ObjectMapper mapper =new ObjectMapper();    
mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);

尽管提到了属性，但出现无法识别的属性异常

Getting unrecognized property exception though the property has been mentioned

java

json

exception

jackson

jsonobject

尽管提到了 属性，但出现无法识别的 属性 异常

Getting unrecognized property exception though the property has been mentioned

java

json

exception

jackson

jsonobject

尽管提到了属性，但出现无法识别的属性异常