LocalDate, LocalDateTime, Timestamp 변환

JS 서울시간

// 서울 시간
const timeStamp = new Date(new Date().getTime() + 9 * 60 * 60 * 1000) 

LocalDateTime > String

    DateTimeFormatter formatter = 
        DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")
        .withZone(ZoneId.of("Asia/Seoul"));

    LocalDateTime ldt = LocalDateTime.now(); // 2024-07-05T09:18:29.417174500
    String now = formatter.format(ldt);      // 2024-07-05 09:18:29.417

Timestamp > LocalDateTime > String

    public void setTtdGateElapsedTime(Timestamp timestamp) {
        DateTimeFormatter formatter = 
		    DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
			
        this.ttdGateElapsedTime = 
		    timestamp.toLocalDateTime().format(formatter);
    }

ORM, Timestamp > Json

TimeStamp -> Json 변환
com.fasterxml.jackson.databind.JsonMappingException 발생

    // String > Timestamp
    private static Timestamp convertStringToTimestamp(String dateString) {
        SimpleDateFormat dateFormat = 
		    new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
			
        java.util.Date parsedDate = null;
		
        try {
            parsedDate = dateFormat.parse(dateString);
        } catch (ParseException e) {
            throw new RuntimeException(e);
        }
        return new Timestamp(parsedDate.getTime());
    }
    
    // ORM, Timestamp > LocalDateTime > String > Json
	list.stream().forEach(item -> {            
        DateTimeFormatter formatter = 
		    DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")
            withZone(ZoneId.of("Asia/Seoul"));
			
        Timestamp timestamp = 
            convertStringToTimestamp(item.get("TTD_TIMESTAMP").toString());
        LocalDateTime ldt = timestamp.toLocalDateTime();
        item.put("TTD_TIMESTAMP", formatter.format(ldt));
    });

UTC 시간 > TimestampString

	Instant now = Instant.now();
    // now = 2024-07-05T00:29:02.705537700Z
    
    DateTimeFormatter formatter = 
        DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")
        .withZone(ZoneId.of("UTC"));
            
    String timestampString = formatter.format(now);
    // timestampString = 2024-07-05 00:29:02.705

SQL

ISO 8601 형식의 UTC 시간을 Timestamp 타입으로 변환

SELECT TO_TIMESTAMP('2024-07-02T08:37:29.352Z', 'YYYY-MM-DD"T"HH24:MI:SS.FF3"Z"')
FROM DUAL;
-- 2024-07-02 08:37:29.352

입력된 시간이 유효한지 검증

    public boolean isValidDate(String dateStr) {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd");
        try {
            LocalDate date = LocalDate.parse(dateStr, formatter);
            return true;
        } catch (DateTimeParseException e) {
            return false;
        }
    }

String 날짜 TimeStamp 형식 변경

import java.sql.Timestamp;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateConverter {
    public static void main(String[] args) {
        String dateString = "20230317";
        Timestamp timestamp = convertStringToTimestamp(dateString);
        System.out.println("Original String: " + dateString);
        System.out.println("Converted Timestamp: " + timestamp);
    }

    public static Timestamp convertStringToTimestamp(String dateString) {
        // 문자열을 LocalDate로 변환
        DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("yyyyMMdd");
        LocalDate localDate = LocalDate.parse(dateString, dateFormatter);

        // LocalDate를 LocalDateTime으로 변환
        LocalDateTime localDateTime = localDate.atStartOfDay();

        // LocalDateTime을 Timestamp로 변환
        Timestamp timestamp = Timestamp.valueOf(localDateTime);

        return timestamp;
    }
}

yyyyMMdd > yyyy.MM.dd

public static String toDotDate(String src) {
        DateTimeFormatter OUT = DateTimeFormatter.ofPattern("yyyy.MM.dd");

        DateTimeFormatter IN_DATE = new DateTimeFormatterBuilder()
                .parseStrict()
                .appendPattern("uuuuMMdd")
                .toFormatter()
                .withResolverStyle(ResolverStyle.STRICT);

        DateTimeFormatter IN_DATETIME = new DateTimeFormatterBuilder()
                .parseStrict()
                .appendPattern("uuuuMMddHHmmss")
                .toFormatter()
                .withResolverStyle(ResolverStyle.STRICT);

        String s = src.trim();

        switch (s.length()) {
            case 8: { // yyyyMMdd
                LocalDate d = LocalDate.parse(s, IN_DATE);
                return OUT.format(d);
            }
            case 14: { // yyyyMMddHHmmss
                LocalDateTime dt = LocalDateTime.parse(s, IN_DATETIME);
                return OUT.format(dt.toLocalDate());
            }
            default:
                return s;
        }
    }