ObjectMapper-读取/写入通用对象

Question

我有一个场景，我将Object推送到队列，队列将在另一端读取。

我正在将对象转换为字符串，将字符串转换为字节。将这些字节推送到队列中。

CollectionObject collectionObject = new CollectionObject();
// This can be any Object. Or at least Iam thinking it's Object class.
collectionObject.setName("Sienna");
String customerMessage = objectMapper.writeValueAsString(collectionObject);
byte[] msg = customerMessage.getBytes(StandardCharsets.UTF_8);

另一方面，我以这种方式阅读这个物体。

String messageFromQueue = new String(msg);
objectMapper.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true);
Object genericObject = objectMapper.readValue(messageFromQueue, new TypeReference<Object>(){});
System.out.println("let's see object"+genericObject);
if(genericObject instanceof CollectionObject)
System.out.println("turned out to be collectionObject "+genericObject);

但支票的例子永远不会得到满足。readValue返回LinkedHashMap对象。

任何帮助，感谢

Answer 1

问题

没有任何内容指示要封送到的类：{"name":"Sienna"}。fasterxml怎么可能猜测它应该封送到哪种类型。

一个解决方案

首先启用默认键入：

objectMapper.enableDefaultTyping();

然后考虑在实际负载周围使用包装器对象：

public class Wrapper {
private Object content;
public Wrapper() {
}
public Wrapper(Object content) {
this.content = content;
}
public Object getContent() {
return content;
}
public void setContent(Object content) {
this.content = content;
}
}

然后写入对象：

String customerMessage = objectMapper.writeValueAsString(new Wrapper(collectionObject));

然后读取对象：

Object genericObject = objectMapper.readValue(messageFromQueue, Wrapper.class).getContent();

在这种情况下，genericObject将是CollectionObject，json是{"content":["CollectionObject",{"name":"Sienna"}]}