com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `java.time.LocalDateTime`

Question

In Json return the field date time:

"date": "2023-09-22 01:07:50.062477"

In class Json:

@JsonDeserialize(using = LocalDateTimeDeserializer.class)
@JsonSerialize(using = LocalDateTimeSerializer.class)
public LocalDateTime date;

Return error:

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of java.time.LocalDateTime (no Creators, like default construct, exist): no String-argument constructor/factory method to deserialize from String value ('2023-09-22 02:11:13.855618')

How to solve?

@JsonDeserialize(using = LocalDateTimeDeserializer.class)
@JsonSerialize(using = LocalDateTimeSerializer.class)
public LocalDateTime date;

Answer 1

you are getting that error since Json is trying to deserialize the date sting into instance of LocalDateTime but it not being able to do that due no constructor or such method on that class.

You can get to solution by creating a custom deserializer class by extending JsonDeserializer and override the deserializer method and return to required by Parsing.

import java.io.IOException;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;

public class CustomLocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {
    private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSS");

    @Override
    public LocalDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
        String dateStr = jsonParser.getValueAsString();
        return LocalDateTime.parse(dateStr, formatter);
    }
}

Then annotate the field with custom deserializer instead.

@JsonDeserialize(using = CustomLocalDateTimeDeserializer.class)
@JsonSerialize(using = LocalDateTimeSerializer.class)
public LocalDateTime date;

I am sure that you have this dependency.

implementation("com.fasterxml.jackson.datatype:jackson-datatype-jsr310")

Hope this works for you. I did have get some shortcut just before 3-4 months. Sorry I forgot that.

Answer 2

Am no sure how you interact from front end, passing json data from the front end or when you call the end point just put this to the @PathVariable or @RequestParam like this in controller class:

@RequestMapping(method = RequestMethod.GET, path = "/v{version}", produces = "application/json")
ResponseEntity<List<Test>> findByDate(@RequestParam(required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) LocalDateTime date)}

Use this standard ISO method.