Throw custom exception while deserializing the Date field using jackson in java

Question

DTO:

@Getter
@Setter
@ToString
public class TestDto {

    @NotNull
    private String id;

    @NotNull
    @DateTimeFormat(pattern = "YYYY-MM-DD'T'hh:mm:ss.SSSZ")
    private Instant timestamp;
}

When I give this input

{"timestamp":"4/23/2018 11:32 PM","id":"132"}

It gives BAD_REQUEST (which it should), but I want to handle this malformed date and throw an exception with my custom exception.

How can I add this?

The pattern is not a valid pattern, and even if it was, it clearly doesn't match the date string in your JSON. Besides, DateTimeFormat has no effect at all on the say Jackson parses dates. It's not a Jackson annotation. — JB Nizet, Mar 17 '19 at 17:25
Yeah, I know it doesn't match. I want to throw a custom exception for this kind of invalid dates. — nirvair, Mar 17 '19 at 17:26
Ah, sorry, I misread. AFAIK, you can't. Jackson throws a Jackson exception when parsing. — JB Nizet, Mar 17 '19 at 17:28
How can I set another status for this kind of cases - when the input is malformed? — nirvair, Mar 17 '19 at 17:29
I know it is, but for this project I need to have different status code. — nirvair, Mar 17 '19 at 17:31
This feature request is proposed: https://github.com/FasterXML/jackson-annotations/issues/130 — dkb, Mar 17 '19 at 17:32
Is it possible for you to have customDeserializer for Instant field? — dkb, Mar 17 '19 at 17:33
@dkb yeah, I can add custom deserializer. How can I do that? — nirvair, Mar 17 '19 at 17:34
https://www.baeldung.com/global-error-handler-in-a-spring-rest-api In there it shows how to make your own custom exception. — Compiler v2, Mar 17 '19 at 17:34
try this one as well https://www.baeldung.com/jackson-deserialization. I do not know exactly how to do this (a bit beyond my level) but I hope these links help. — Compiler v2, Mar 17 '19 at 17:35
@Compilerv2 didn't work. I mean, I'm not able to get the value - `node.get("timestamp")` — nirvair, Mar 17 '19 at 17:45

dkb · Accepted Answer · 2019-03-17T18:28:09.467

Since OP requested feature is not supported yet: https://github.com/FasterXML/jackson-annotations/issues/130

Trying to do the same thing with a bit longer approach by using custom deserializer for a field timestamp

Custom exception class:

import com.fasterxml.jackson.core.JsonProcessingException;

public class MyException extends JsonProcessingException {
    public MyException(String message) {
        super(message);
    }
}

Custom Deserializer class:

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.time.Instant;
import java.util.Date;
public class InstantDeserializer extends StdDeserializer<Instant> {

public InstantDeserializer() {
    this(null); 
} 

public InstantDeserializer(Class<?> vc) {
    super(vc); 
}

private SimpleDateFormat sdf = new SimpleDateFormat("YYYY-MM-DD'T'hh:mm:ss.SSS'Z'");

@Override
public Instant deserialize(JsonParser jp, DeserializationContext ctxt)
  throws IOException, JsonProcessingException {
    JsonNode node = jp.getCodec().readTree(jp);
    Date date = null;
    try {
        date = sdf.parse(node.asText());
    } catch (Exception e) {
        throw new MyException("Instant field deserialization failed");
    }
    return date.toInstant();
}
}

Updated TestDto class:

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import org.springframework.format.annotation.DateTimeFormat;

import javax.validation.constraints.NotNull;
import java.time.Instant;

@Getter
@Setter
@ToString
public class TestDto {

    @NotNull
    private String id;

    @NotNull
    @JsonDeserialize(using = InstantDeserializer.class)
    @DateTimeFormat(pattern = "YYYY-MM-DD'T'hh:mm:ss.SSS'Z'")
    private Instant timestamp;
}

Invalid Input request:

{"timestamp":"4/23/2018 11:32 PM","id":"132"}

Response:

{
    "timestamp": 1552845180271,
    "status": 400,
    "error": "Bad Request",
    "message": "JSON parse error: Instant field deserialization failed; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Instant field deserialization failed (through reference chain: TestDto[\"timestamp\"])"
}

Valid Input Request:

{"timestamp":"2018-04-23T11:32:22.213Z","id":"132"}

Response:

{
    "id": "132",
    "timestamp": {
        "epochSecond": 1514700142,
        "nano": 213000000
    }
}

If you do not like the way timestamp field is getting deserialized and would like to change that, this SO post will be helpful.

Thanks a lot! Is there any other alternative to SimpleDateFormat? Also when you return Instant.now(), does this set the value to that field? — nirvair, Mar 17 '19 at 17:58
It also throws exception for a valid date: 2019-03-17T16:51:51.304Z — nirvair, Mar 17 '19 at 18:21
For some reasons, I'm not able to understand why, the serializer stopped throwing exception (tried RuntimeException too) — nirvair, Mar 17 '19 at 19:13
It doesnt work, exception is not catched in ControllerAdvice — Matley, Mar 03 '21 at 01:01

Throw custom exception while deserializing the Date field using jackson in java

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