有什么办法可以在不中断反序列化过程的情况下忽略JsonProcessingException

Question

I'm looking into a solution for Jackson deserialization JSON to an instance of a class without breaking the whole process, currently when I do something like:

If Actor.class was like:

@JsonInclude(JsonInclude.Include.NON_EMPTY)
@JsonPropertyOrder(alphabetic = true)
public abstract class BaseDTO {

}

public class Character extend BaseDTO {
    private LocalDateTime updatedDate;
    private String name;

    // Setters and getters 
}

and deserialize json {"updatedDate":"N/A", "name": "Jon Snow"} like:

String json = "{\"updatedDate\":\"N/A\", \"name\": \"Jon Snow\"}";
ObjectMapper mapper = new ObjectMapper();
final Character character = mapper.reader().forType(Character.class).readValue(json);

Or as Play Framework directly:

final Character character = Json.fromJson(json, Character.class);

I definitely will get an exception like:

Caused by: com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.time.LocalDateTime` from String "N/A": Text 'N/A' could not be parsed at index 0

And InvalidFormatException actually is a JsonProcessingException , there is also MismatchedInputException and other exceptions, so I need somehow gracefully continue with processing and get the object character and have name value at least instead of stopping it at all.

I prefer to:

• Use annotations to config the parser or any solution to be applied to BaseDTO .
• Logging the issue in the log file so I know that something wrong happened.

I really can't find the way right now without a huge effort, so I wonder if there is any out-of-box solution do that without re-invent the wheel.

Answer 1

I am assuming that you wannt ot consider string like N/A as null. Using a custom deserializer it can be achieved like this.

class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {
    @Override
    public LocalDateTime deserialize(JsonParser p, DeserializationContext context) throws IOException {
        if ("N/A".equals(p.getText())) return null;
        return LocalDateTime.from(DateTimeFormatter.ISO_OFFSET_DATE_TIME.parse(p.getText()));
    }
}

Hope this helps!