Java Jackson多态反序列化
我对Jackson和类型层次结构有以下问题。我正在序列化一个类Java Jackson多态反序列化,java,json,polymorphism,jackson,Java,Json,Polymorphism,Jackson,我对Jackson和类型层次结构有以下问题。我正在序列化一个类SubA,它将Base扩展为字符串, 然后尝试将其反序列化回来。当然,在编译时,系统不知道它是否会 Base或SubA,因此我期待一个Base,如果它是SubA,我会在之后执行一些其他操作 我的Base类看起来像: @JsonTypeInfo( use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type") @JsonSu
SubA
,它将Base
扩展为字符串
,
然后尝试将其反序列化回来。当然,在编译时,系统不知道它是否会
Base
或SubA
,因此我期待一个Base
,如果它是SubA
,我会在之后执行一些其他操作
我的Base
类看起来像:
@JsonTypeInfo(
use = JsonTypeInfo.Id.NAME,
include = JsonTypeInfo.As.PROPERTY,
property = "type")
@JsonSubTypes({
@Type(value = SubA.class, name = "SubA")
})
public class Base {
protected String command; // +get +set
protected String type; // +get +set
}
。。。以及从基派生的类
:
@JsonTypeName("SubA")
public class SubA extends Base {
private AnotherClass anotherClass; // +get +set
private String test; // +get +set
@JsonIgnore
@Override
public String getType() {
return "SubA";
}
}
。。。我正在尝试执行以下代码:
ObjectMapper mapper = new ObjectMapper();
ObjectWriter ow = mapper.writer().withDefaultPrettyPrinter();
Base payload = new SubA(); // + setting anotherClass as well as test variables
String requestStringSend = ow.writeValueAsString(payload);
System.out.println("Sending: " + requestStringSend);
Base received = mapper.readValue(requestStringSend, Base.class);
String requestStringReceived = ow.writeValueAsString(received);
System.out.println("Received: " + requestStringReceived);
字符串requestStringSend
为:
Sending: {
"command" : "myCommand",
"type" : "SubA",
"anotherClass" : {
"data" : "someData"
},
"test" : "test123"
}
但我一次又一次地犯同样的错误。映射器现在知道如何处理另一个类
参数-它不存在于Base
中。但我认为映射程序会将其转换为SubA
类
Exception in thread "main" org.codehaus.jackson.map.exc.UnrecognizedPropertyException: Unrecognized field "anotherClass" (Class com.test.Base), not marked as ignorable
at [Source: java.io.StringReader@1256ea2; line: 4, column: 21] (through reference chain: com.test.Base["anotherClass"])
at org.codehaus.jackson.map.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:53)
at org.codehaus.jackson.map.deser.StdDeserializationContext.unknownFieldException(StdDeserializationContext.java:267)
at org.codehaus.jackson.map.deser.std.StdDeserializer.reportUnknownProperty(StdDeserializer.java:649)
at org.codehaus.jackson.map.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:635)
at org.codehaus.jackson.map.deser.BeanDeserializer.handleUnknownProperty(BeanDeserializer.java:1355)
at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:717)
at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)
at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2723)
at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1854)
at com.test.Foo.main(Foo.java:32)
我查看了以下问题/资源:
ObjectMapper
(我可以从例外的包名中看到后者是Jackson)。注释和映射器的版本必须匹配;否则注释将被忽略,这将解释您看到的问题。您使用的是哪个版本的Jackson
?我检查了您的示例,查看了Jackson
2.3.2(com.fasterxml.Jackson),一切正常。谢谢,这就是解决方案!我使用了2.x注释,但是使用了1.x ObjectMapper!