Convert Timestamp to Long in Java

🎓 Top 15 Udemy Courses (80-90% Discount): My Udemy Courses - Ramesh Fadatare — All my Udemy courses are real-time and project oriented courses.

▶️ Subscribe to My YouTube Channel (178K+ subscribers): Java Guides on YouTube

▶️ For AI, ChatGPT, Web, Tech, and Generative AI, subscribe to another channel: Ramesh Fadatare on YouTube

In Java, dealing with dates and times is a common task in many applications. Sometimes, you may need to convert a Timestamp object into a long value, which represents the number of milliseconds since January 1, 1970, 00:00:00 GMT. This blog post will guide you through the process of converting a Timestamp to a long value in Java. 

Understanding Timestamp and Long 

Timestamp: In Java, a Timestamp object represents a point in time, precise to nanoseconds. It's commonly used in JDBC to handle SQL TIMESTAMP data type. 

Long: A long value in Java is a 64-bit integer. When we talk about converting a Timestamp to a long, we refer to representing the same point in time as milliseconds since the Unix epoch. 

Method 1: Using getTime() Method 

The simplest way to convert a Timestamp to a long is by using the getTime() method. This method returns the number of milliseconds since January 1, 1970, 00:00:00 GMT. 

Code Example

import java.sql.Timestamp;

public class TimestampConverter {

    public static void main(String[] args) {
        // Creating a Timestamp object
        Timestamp timestamp = new Timestamp(System.currentTimeMillis());

        // Converting Timestamp to long
        long milliseconds = timestamp.getTime();

        // Display the result
        System.out.println("Timestamp as long: " + milliseconds);
    }
}

Output:

Timestamp as long: [current time in milliseconds]

Method 2: Using toInstant().toEpochMilli() (Java 8 and later) 

If you are using Java 8 or later, you can take advantage of the Instant class for this conversion. This method is more versatile and aligns with the modern Java Date and Time API. 

Code Example

import java.sql.Timestamp;
import java.time.Instant;

public class TimestampConverter {

    public static void main(String[] args) {
        // Creating a Timestamp object
        Timestamp timestamp = new Timestamp(System.currentTimeMillis());

        // Converting Timestamp to long
        long milliseconds = timestamp.toInstant().toEpochMilli();

        // Display the result
        System.out.println("Timestamp as long: " + milliseconds);
    }
}

Output:

Timestamp as long: [current time in milliseconds]

Conclusion 

Converting a Timestamp to a long value in Java is straightforward and can be done using either the getTime() method for simplicity or the toInstant().toEpochMilli() for a more modern approach. Both methods are effective and depend on your project's Java version and coding style preferences. 

This conversion is essential for applications that require time calculations or storage of dates in a numeric format.

My Top and Bestseller Udemy Courses. The sale is going on with a 70 - 80% discount. The discount coupon has been added to each course below:

Build REST APIs with Spring Boot 4, Spring Security 7, and JWT

🆕 High-Demand 80–90% OFF

[NEW] Learn Apache Maven with IntelliJ IDEA and Java 25

🆕 High-Demand 80–90% OFF

ChatGPT + Generative AI + Prompt Engineering for Beginners

🚀 Trending Now 80–90% OFF

Spring 7 and Spring Boot 4 for Beginners (Includes 8 Projects)

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Building Real-Time REST APIs with Spring Boot - Blog App

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Building Microservices with Spring Boot and Spring Cloud

🌟 Top Rated 80–90% OFF
Available in Udemy for Business

Java Full-Stack Developer Course with Spring Boot and React JS

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Build 5 Spring Boot Projects with Java: Line-by-Line Coding

🌟 Top Rated 80–90% OFF

Testing Spring Boot Application with JUnit and Mockito

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Spring Boot Thymeleaf Real-Time Web Application - Blog App

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Master Spring Data JPA with Hibernate

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Spring Boot + Apache Kafka Course - The Practical Guide

🎓 Student Favorite 80–90% OFF
Available in Udemy for Business

Java Testing: Mastering JUnit 5 Framework

🆕 New 80–90% OFF

Reactive Programming in Java: Spring WebFlux and Testing

🌟 Top Rated 80–90% OFF

Spring Boot + RabbitMQ Course - The Practical Guide

🌟 Top Rated 80–90% OFF
Available in Udemy for Business

Functional Programming in Java (Includes Java Collections)

🎓 Student Favorite 80–90% OFF

ChatGPT for Java Developers: Boost Your Productivity with AI

🚀 Trending Now 80–90% OFF