java 8 sql timestamp examples   

Several examples showing how to use:

import java.sql.Timestamp;

in java 8 - with ZonedDateTime, using with current time and examples on compability with older java versions.

In this post:

• Java 8 SQL timestamp and ZonedDateTime
• Return now or the beginning of counting as timestamp
• Convert timestamp from today's date
• Converting timestamp to instant
• Converting SimpleDateFormat to timestamp
• The complete example

Java 8 SQL timestamp and ZonedDateTime

Converting date from the new java 8 ZonedDateTime to sql timestamp:

ZonedDateTime -> timestamp
2017-11-23T17:00:00-0700 -> 2017-11-24 02:00:00.0

String start_time = "2017-11-23T17:00:00-0700";

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ");
ZonedDateTime formatDateTime = ZonedDateTime.parse(start_time, formatter);
Instant instant2 = formatDateTime.toInstant();

System.out.println(new Timestamp(instant2.toEpochMilli()));

result:

2017-11-24 02:00:00.0

Note that time zone is considered and it's giving a difference from 2 hours.

Several examples on the time addition - my zone has two hours difference with the GTM so in order to get exactly the same time I need to use:

"2017-11-23T17:00:00+0200" -> 2017-11-24 00:00:00.0
"2017-11-23T17:00:00-1000" -> 2017-11-24 05:00:00.0
"2017-11-23T17:00:00-0000" -> 2017-11-23 19:00:00.0

Return now or the beginning of counting as timestamp

In order to get now or the begining of counting (1970-01-01) we can use:

Timestamp timestamp = new Timestamp(System.currentTimeMillis());
System.out.println(timestamp);

Timestamp timestampDate = new Timestamp(0);
System.out.println(timestampDate);

result:

2018-03-01 11:05:53.78
1970-01-01 02:00:00.0

Convert timestamp from today's date

The simplest example is when you want to get today as date and convert it to timestamp:

new Date() -> 2018-03-01 11:05:53.78

Date date = new Date();
System.out.println(new Timestamp(date.getTime()));

result:

2018-03-01 11:05:53.78

Converting timestamp to instant

Converting timestamp to instant and the reverse operation:

2018-03-01T09:11:12.603Z <-> 1519895472603

can be done by methods: toInstant() and from(instant)

Timestamp timestamp = new Timestamp(System.currentTimeMillis());
Instant instant = timestamp.toInstant();
System.out.println(instant);

Timestamp timestampInstant = Timestamp.from(instant);
System.out.println(timestampInstant.getTime());

result:

2018-03-01T09:11:12.603Z
1519895472603

Converting SimpleDateFormat to timestamp

If you are using older versions of java you can use this code which is compabitle with java versions before java 8:

SimpleDateFormat -> sql timestamp
"2020/03/01 22:05:15" -> 2020-03-01 22:05:15.0

String myDate = "2020/03/01 22:05:15";
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date customDate = sdf.parse(myDate);
long millis = customDate.getTime();

Date date1 = new Date(millis);
System.out.println(new Timestamp(date1.getTime()));

result:

2020-03-01 22:05:15.0

The complete example

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;
import java.sql.Timestamp;
import java.time.Instant;

public class TimestampTest {

    public static void main(String[] args) throws ParseException {

        //
        //simple date format
        //
        String myDate = "2020/03/01 22:05:15";
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
        Date customDate = sdf.parse(myDate);
        long millis = customDate.getTime();


        Date date1 = new Date(millis);
        System.out.println(new Timestamp(date1.getTime()));

        //
        //simple date format
        //
        String start_time = "2017-11-23T17:00:00-0700";

        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ");
        ZonedDateTime formatDateTimeZ = ZonedDateTime.parse(start_time, formatter);
        Instant instant2 = formatDateTimeZ.toInstant();
        System.out.println(instant2);
        System.out.println(new Timestamp(instant2.toEpochMilli()));

        //
        // time stamp from today
        //

        Date date = new Date();
        System.out.println(new Timestamp(date.getTime()));

        //
        // time stamp beginning
        //

        Timestamp timestampDate = new Timestamp(0);
        System.out.println(timestampDate);

        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
        System.out.println(timestamp);

        //
        // time stamp to instant
        //
        
        System.out.println(timestamp.getTime());
        Instant instant = timestamp.toInstant();
        System.out.println(instant);
        System.out.println(instant.toEpochMilli());
        Timestamp timestampInstant = Timestamp.from(instant);
        System.out.println(timestampInstant.getTime());
    }
}