Java unix timestamp to string

Java sql.Timestamp toString() method with example

The toString() method of the java.sql.Timestamp class returns the JDBC escape format of the time stamp of the current Timestamp object as String variable.

i.e. using this method you can convert a Timestamp object to a String.

//Retrieving the Time object Timestamp timestampObj = rs.getTimestamp("DispatchTimeStamp"); //Converting the Time object to String format String time_stamp = timestampObj.toString();

Example

Let us create a table with the name dispatches_data in MySQL database using CREATE statement as shown below:

CREATE TABLE dispatches_data( ProductName VARCHAR(255), CustomerName VARCHAR(255), DispatchTimeStamp timestamp, Price INT, Location VARCHAR(255));

Now, we will insert 5 records in dispatches_data table using INSERT statements:

insert into dispatches_data values('Key-Board', 'Raja', TIMESTAMP('2019-05-04', '15:02:45'), 7000, 'Hyderabad'); insert into dispatches_data values('Earphones', 'Roja', TIMESTAMP('2019-06-26', '14:13:12'), 2000, 'Vishakhapatnam'); insert into dispatches_data values('Mouse', 'Puja', TIMESTAMP('2019-12-07', '07:50:37'), 3000, 'Vijayawada'); insert into dispatches_data values('Mobile', 'Vanaja' , TIMESTAMP ('2018-03-21', '16:00:45'), 9000, 'Chennai'); insert into dispatches_data values('Headset', 'Jalaja' , TIMESTAMP('2018-12-30', '10:49:27'), 6000, 'Goa');

Following JDBC program establishes a connection with the database and retrieves the contents of the dispatches_data table.

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.sql.Timestamp; public class Timestamp_toString < public static void main(String args[]) throws SQLException < //Registering the Driver DriverManager.registerDriver(new com.mysql.jdbc.Driver()); //Getting the connection String mysqlUrl = "jdbc:mysql://localhost/mydatabase"; Connection con = DriverManager.getConnection(mysqlUrl, "root", "password"); System.out.println("Connection established. "); //Creating a Statement object Statement stmt = con.createStatement(); //Query to retrieve the contents of the dispatches_data table String query = "select * from dispatches_data"; //Executing the query ResultSet rs = stmt.executeQuery(query); while (rs.next()) < System.out.println("Product Name: " + rs.getString("ProductName")); System.out.println("Customer Name: " + rs.getString("CustomerName")); Timestamp timeStampObj = rs.getTimestamp("DispatchTimeStamp"); //Converting the Time object to String format String timeStamp = timeStampObj.toString(); System.out.println("Dispatch time stamp in String format: " + timeStamp); System.out.println("Location: " + rs.getString("Location")); System.out.println(); >> >

Here, in this program while retrieving the column values, we have converted the DeliveryTime value from the Timestamp object to string format using the toString() method of the Timestamp class and trying to display it.

Output

Connection established. Product Name: Key-Board Customer Name: Raja Dispatch time stamp in String format: 2019-05-04 15:02:45.0 Location: Hyderabad Product Name: Earphones Customer Name: Roja Dispatch time stamp in String format: 2019-06-26 14:13:12.0 Location: Vishakhapatnam Product Name: Mouse Customer Name: Puja Dispatch time stamp in String format: 2019-12-07 07:50:37.0 Location: Vijayawada Product Name: Mobile Customer Name: Vanaja Dispatch time stamp in String format: 2018-03-21 16:00:45.0 Location: Chennai Product Name: Headset Customer Name: Jalaja Dispatch time stamp in String format: 2018-12-30 10:49:27.0 Location: Goa

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Mastering Unix Timestamps in Java: A Comprehensive Guide

Learn how to work with Unix timestamps in Java and convert them to date and time formats with this comprehensive guide. Avoid common issues and use best practices for storing Unix timestamps.

• Understanding Unix Timestamps
• Converting Unix Timestamps to Date and Time Formats
• Date and Time in Java using Unix Epoch Time
• Working with Timezones
• Best Practices for Working with Unix Timestamps in Java
• Common Issues Related to Unix Timestamps in Java
• Other Java code samples for Unix timestamps
• Conclusion
• How to convert timestamp to Unix time in Java?
• How to get Unix timestamp from date?
• How to get epoch timestamp in Java?
• How to store epoch time in Java?

As a Java developer, working with Unix timestamps is a necessary skill to have. Unix timestamps represent the number of seconds elapsed since January 1st, 1970, at 00:00:00 UTC. In this guide, we will cover everything you need to know about working with Unix timestamps in Java, including how to convert them to date and time formats.

Understanding Unix Timestamps

Unix timestamps are an essential part of representing time in computer systems. Unix timestamps are stored as long numbers to avoid the 2038 year problem. In Java, you can get the Unix timestamp by using methods such as Instant.now(), Date.getTime(), or new Date().getTime(). It is important to store Unix timestamps as long numbers to avoid overflow errors that occur when storing them as Java int values.

Converting Unix Timestamps to Date and Time Formats

Converting Unix Timestamps to date and time formats is a common task in Java programming. To convert a Unix timestamp to a human- readable date and time format , you can use methods such as Date(), toInstant(), or DateTime(). You can also use System.currentTimeMillis() and Instant.now().toEpochMillis() to get the Unix epoch time in milliseconds.

Java 8 introduced the java.time package for working with dates and times. This package provides a lot of useful classes and methods for working with time. The SimpleDateFormat class can be used to parse a timestamp string into Unix time in Java. The java.sql.Timestamp class is a thin wrapper around java.util.Date that allows the JDBC API to identify this as an SQL TIMESTAMP value.

Date and Time in Java using Unix Epoch Time

This video introduces the concept of Epoch Time and in particular Unix Epoch time. It details Duration: 56:07

Timezones matter only when displaying a timestamp in a user’s local time. Working with timezones can be complex, and it’s important to be aware of potential issues when working with Unix timestamps in different timezones. The Instant class stores the number of seconds from the Java epoch, making it easy to work with timezones. On the other hand, the java.util.Calendar class is long outdated and poorly designed.

Best Practices for Working with Unix Timestamps in Java

best practices for working with unix timestamps in Java include using long numbers and avoiding storing them as Java int values. Advancements in Java 8’s java.time package have made working with dates and times easier and more efficient. A cheatsheet for working with Unix timestamps in Java can be helpful for quick reference.

Common Issues Related to Unix Timestamps in Java

Common issues related to Unix timestamps in Java include the 2038 year problem and timezone inconsistencies. Tips and tricks for working with Unix timestamps in Java include using methods such as System.currentTimeMillis() and Instant.now() and being mindful of timezone differences. Java is a popular programming language for working with Unix timestamps and offers many built-in methods for working with dates and times.

Other Java code samples for Unix timestamps

In Java as proof, java timestamp code sample

Timestamp timestamp = new Timestamp(System.currentTimeMillis()); //2016-11-16 06:43:19.77 Copy

In Java , for instance, java get unix timestamp code sample

long unixTime = System.currentTimeMillis() / 1000L;

In Java case in point, get current unix timestamp java code sample

System.currentTimeMillis() / 1000L;

Conclusion

Working with Unix timestamps in Java is an essential skill for any Java developer. By understanding how to work with Unix timestamps, you can ensure that your applications accurately represent time and avoid common issues. Remember to use best practices for storing Unix timestamps, be mindful of timezone differences, and take advantage of Java’s built-in methods for working with dates and times.

Frequently Asked Questions — FAQs

What is a Unix timestamp and why is it important in Java programming?

A Unix timestamp represents the number of seconds elapsed since January 1st, 1970, at 00:00:00 UTC. It is important in Java programming as it is an essential way of representing time in computer systems.

How can I get the Unix timestamp in Java?

You can get the Unix timestamp in Java by using methods such as Instant.now(), Date.getTime(), or new Date().getTime().

What are the best practices for storing Unix timestamps in Java?

The best practices for storing Unix timestamps in Java include using long numbers and avoiding storing them as Java int values.

How can I convert a Unix timestamp to date and time formats in Java?

You can convert a Unix timestamp to date and time formats in Java by using methods such as Date(), toInstant(), or DateTime().

What are the common issues related to Unix timestamps in Java?

Common issues related to Unix timestamps in Java include the 2038 year problem and timezone inconsistencies. It is important to be mindful of timezone differences and use methods such as System.currentTimeMillis() and Instant.now().

What are some tips for working with Unix timestamps in Java?

Some tips for working with Unix timestamps in Java include using the java.time package introduced in Java 8, using a cheatsheet for quick reference, and avoiding the use of the outdated java.util.Calendar class.

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Epoch Converter and Date/Time in Java

An easy way to get the current date and time in Java is using the Date class which is available in the java.util package.

 import java.util.Date; class Main < public static void main(String[] args) < Date date = new Date(); System.out.println(date); >> 

Output:

 Sat Feb 16 03:50:30 UTC 2019 

Formatting Dates

There are multiple ways to format dates.

 import java.util.*; import java.text.*; class Main < public static void main(String[] args) < //1st way System.out.println(); Date date = new Date(); System.out.printf("%1$s %2$tB %2$td, %2$tY", "Current date:", date); //2nd way System.out.println("\n"); Date d = new Date(); SimpleDateFormat ft = new SimpleDateFormat ("E yyyy-MM-dd 'at' hh:mm:ss a zzz"); System.out.println("Current Date and Time: " + ft.format(d)); //3rd way System.out.println(); Date d2 = new Date(); // display time and date String str = String.format("Current Date and Time: %tc", d2 ); System.out.printf(str); >> 

Output:

 Current date: February 16, 2019 Current Date and Time: Sat 2019-02-16 at 03:52:46 AM UTC Current Date and Time: Sat Feb 16 03:52:46 UTC 2019 

Click here to learn more about formatting dates.

Convert from Epoch to Human Readable Date

Here is the way in Java to convert epoch or unix time to a human readable date.

 import java.util.*; class Main < public static void main(String[] args) < //You could start with a string representation of epoch String epochString = "1549499024"; long epoch = Long.parseLong( epochString ); System.out.println("Convert Epoch " + epoch + " to date: "); Date d = new Date( epoch * 1000 ); //convert epoch seconds to microseconds System.out.println(d); //You could start with a long number epoch long epoch2 = 1550544173; System.out.println(new Date(epoch2 * 1000)); >> 

Output:

 Convert Epoch 1549499024 to date: Thu Feb 07 00:23:44 UTC 2019 Tue Feb 19 02:42:53 UTC 2019 

Convert from Human Readable Date to Epoch

Here is the way in Java to format the date to show as epoch or unix time.

 import java.util.*; class Main < public static void main(String[] args) < //Get the unix timestamp using Date Date currentDate = new Date(); long epoch = currentDate.getTime() / 1000; System.out.println("Epoch: " + epoch); //You could use string format to format to unix timestamp Date date = new Date(); String str = String.format("Epoch using string format: %ts", date ); System.out.printf(str); >> 

Output:

 Epoch: 1550544489 Epoch using string format: 1550544489 

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Java Unix time

Java Unix time tutorial shows how to compute Unix time in Java.

(also known as POSIX time or epoch time), is a system for describing a point in time, defined as the number of seconds that have elapsed since 00:00:00 Coordinated Universal Time (UTC), Thursday, 1 January 1970, minus the number of leap seconds that have taken place since then.

Unix time is widely used on Unix-like operating systems but also in many other computing systems and file formats. It is often used by webmasters because a Unix timestamp can represent all time zones at once.

Unix timestamps should be stored as long numbers; if they are store as Java int values, then this leads to a 2038 year problem. 32-bit variables cannot encode times after 03:14:07 UTC on 19 January 2038.

We can use the date command to determine Unix time on Linux. Unix time can be determined on the https://www.unixtimestamp.com/.

Java Unix time example

The following example computes the Unix time.

package com.zetcode; import java.time.Instant; import java.util.Date; public class JavaUnixTimeEx < public static void main(String[] args) < long ut1 = Instant.now().getEpochSecond(); System.out.println(ut1); long ut2 = System.currentTimeMillis() / 1000L; System.out.println(ut2); Date now = new Date(); long ut3 = now.getTime() / 1000L; System.out.println(ut3); >>

There are three basic ways to compute Unix time in Java.

long ut1 = Instant.now().getEpochSecond(); System.out.println(ut1);

Since Java 8, it is possible to use Instant and its getEpochSecond to compute the Unix time.

long ut2 = System.currentTimeMillis() / 1000L; System.out.println(ut2);

Here we compute the Unix time with System.currentTimeMillis method. We need to transform milliseconds to seconds.

Date now = new Date(); long ut3 = now.getTime() / 1000L; System.out.println(ut3);

We can also use the old Date class to compute the Unix time.

In this article we have shown how to compute Unix time in Java.

Author

My name is Jan Bodnar and I am a passionate programmer with many years of programming experience. I have been writing programming articles since 2007. So far, I have written over 1400 articles and 8 e-books. I have over eight years of experience in teaching programming.

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