I have a situation where I need to parse an array of JSON objects that are not identical.
So for example:
[
{ "type": "type1", ..... type1 contents .... },
{ "type": "type2", ..... type2 contents .... },
....
{ "type": "type1", ..... type1 contents .... }
]
The number of types is limited and the contents of each type are well can be defined but it is not possible to define a single type of object that will hold the contents.
Is there a way to parse them with Jackson?
P.S. I am trying to avoid writing a custom parser if I can help it.
I would use
com.fasterxml.jackson.databind.JsonNode.
JsonNode parsed = objectMapper
.readValue("[{\"name\": \"a\"},{\"type\":\"b\"}]", JsonNode.class);
This class has tons of utility methods to work with.
Or specific for arrays you can use:
com.fasterxml.jackson.databind.node.ArrayNode
ArrayNode value = objectMapper
.readValue("[{\"name\": \"a\"},{\"type\":\"b\"}]", ArrayNode.class);
EDIT
Sorry, I have misread your question, you can use @JsonTypeInfo for polymorphic serialization/deserialization:
public static void main(String args[]) throws JsonProcessingException {
//language=JSON
String data = "[{\"type\":\"type1\", \"type1Specific\":\"this is type1\"},{\"type\":\"type2\", \"type2Specific\":\"this is type2\"}]";
ObjectMapper objectMapper = new ObjectMapper();
List<BaseType> parsed = objectMapper.readValue(data, new TypeReference<List<BaseType>>() {});
System.out.println(parsed);
}
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", include = JsonTypeInfo.As.PROPERTY)
@JsonSubTypes(value = {
@JsonSubTypes.Type(value = Type1.class, name = "type1"),
@JsonSubTypes.Type(value = Type2.class, name = "type2")
})
static public abstract class BaseType {
public String type;
}
static public class Type1 extends BaseType {
public String type1Specific;
@Override
public String toString() {
return "Type1{" +
"type1Specific='" + type1Specific + '\'' +
'}';
}
}
static public class Type2 extends BaseType {
public String type2Specific;
@Override
public String toString() {
return "Type2{" +
"type2Specific='" + type2Specific + '\'' +
'}';
}
}
Here are the docs:
https://github.com/FasterXML/jackson-docs/wiki/JacksonPolymorphicDeserialization
Hope this helps.
And the result would be:
[Type1{type1Specific='this is type1'}, Type2{type2Specific='this is type2'}]