Json string from LocalDateTime(java 8) in Spring MVC

Question

have trouble in LocalDateTime(Java 8) Formatting in Spring MVC framework

my VO is like under code

in mySQL w_date field is DATETIME and recode like "2015-12-25 23:18:22"

public class HistoryBoard { 
    @JsonFormat(pattern="yyyy-MM-dd")
    @DateTimeFormat(iso = DateTimeFormat.ISO.TIME)
    private LocalDateTime w_date;


    public LocalDateTime getW_date() {
        return w_date;
    }

    public HistoryBoard setW_date(String w_date) {
        DateTimeFormatter sdf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.S");
        this.w_date = LocalDateTime.parse(w_date, sdf);
        return this;
    }
}

add maven dependency

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
    <version>2.5.3</version>
</dependency>

and add @JsonFormat(pattern="yyyy-MM-dd") in field value w_date

but still json get Object like

"w_date":{"dayOfMonth":25,"dayOfWeek":"FRIDAY","month":"DECEMBER","year":2015,"dayOfYear":359,"monthValue":12,"hour":23,"minute":18,"second":22,"nano":0,"chronology":{"id":"ISO","calendarType":"iso8601"}

json page Controller code

@RequestMapping(value = "/listJson.do")
public @ResponseBody Object listJson(Map<String, Object> commandMap, ModelMap model) throws Exception {
    List<HistoryBoard> list = boardService.selectBoardList(commandMap);
    return list;

}

Answer 1

A similar question is answered here. You may have to add @JsonSerialize(using = LocalDateTimeSerializer.class) to your field.

You can also create a custom serializer like below:

public class CustomLocalDateTimeSerializer extends JsonSerializer<LocalDateTime>{

    @Override
    public void serialize(LocalDateTime dateTime, JsonGenerator generator, SerializerProvider sp)
            throws IOException, JsonProcessingException {
        String formattedDateTime = dateTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd")); 
        generator.writeString( formattedDateTime);
    }

}

and use that custom serializer in your LocalDateTime field:

@JsonSerialize(using = CustomLocalDateTimeSerializer.class)
private LocalDateTime w_date;