问题
let's say, i have a class
public class A{
private UUID typeId;
private B data;
}
public abstract class B{
private String a;
}
public class BChildOne extends B{
... some variables
}
public class BChildTwo extends B{
... some variables
}
type of class B is changing, according to A's typeId , so if typeId of A is "XXX", type of data field is BChildOne, and if typeId of A is "YYY", type of data field is BChildTwo.
how can i achive that?
so for i tried that;
@JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY, getterVisibility =
JsonAutoDetect.Visibility.NONE, setterVisibility =
JsonAutoDetect.Visibility.NONE)
@JsonIgnoreProperties(ignoreUnknown = true)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include =
JsonTypeInfo.As.EXTERNAL_PROPERTY , property = "typeId")
@JsonSubTypes({
@JsonSubTypes.Type(value = BChildOne.class, name = "40ad2fe6-e672-4f0e-
986e-
619c7a1a3223") }
)
public abstract class B{
but i got following error;
Unexpected token (END_OBJECT), expected FIELD_NAME: missing property 'typeId' that is to contain type id (for class B)
which is obvious, because typeId field is in class A not B.
回答1:
Assuming that your JSON documents are like:
{
"type": "foo",
"data": {
"someCommonProperty": "common property",
"fooProperty": "foo specific property"
}
}
{
"type": "bar",
"data": {
"someCommonProperty": "common property",
"barProperty": "bar specific property"
}
}
You can use:
public class Wrapper {
private String type;
@JsonTypeInfo(use = Id.NAME, property = "type", include = As.EXTERNAL_PROPERTY)
@JsonSubTypes(value = {
@JsonSubTypes.Type(value = Foo.class, name = "foo"),
@JsonSubTypes.Type(value = Bar.class, name = "bar")
})
private AbstractData data;
// Getters and setters
}
public abstract class AbstractData {
private String someCommonProperty;
// Getters and setters
}
public class Foo extends AbstractData {
private String fooProperty;
// Getters and setters
}
public class Bar extends AbstractData {
private String barProperty;
// Getters and setters
}
In this approach, @JsonTypeInfo is set to use type
as an external property to determine the right class to map the data
property. The JSON document can be deserialized as following:
ObjectMapper mapper = new ObjectMapper();
Wrapper wrapper = mapper.readValue(json, Wrapper.class);
回答2:
I had the same serialization issue once and I made an implementation like this. see the code below.
protected Entity serialize(Object entity) throws Exception {
try {
if ( entity instanceof AbstractProcessRequest ) {
AbstractProcessRequest request = (AbstractProcessRequest) entity;
String value = mapper.writeValueAsString(request.prepareJSONRequest());
logger.info("Telesales String json request " + value);
return new Entity(value, UTF_8);
} else {
String value = mapper.writeValueAsString(entity);
return new StringEntity(value, UTF_8);
}
} catch (Exception e) {
logger.error("Telesales --> Error occured serializing entity", e);
throw e;
}
}
To achieve generic structure an execute method is created in some service class like below.
private <T> T execute(Object entity, Class<T> clazz, HttpRequestBase request, String contentType) throws Exception {
来源:https://stackoverflow.com/questions/51018823/jackson-polymorphic-deserialization-via-field