Converting JSON long to a Date in Java Using Jackson

Learn how to effortlessly convert a JSON long timestamp to a human-readable date format in Java with Jackson. This guide provides a step-by-step explanation and helpful code examples for customizing deserialization.
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Converting JSON Long to a Date in Java Using Jackson

When working with JSON data in Java, it's common to encounter timestamps represented as long values. If you're utilizing a library like Jackson to parse JSON, you may want to convert those long timestamps into more readable date formats. This guide will guide you through converting a JSON long to a date in Java using Jackson effectively.

Problem Overview

Consider a class representing plugins, where the createdAt field stores a long timestamp indicating when a plugin was created. For example, the JSON data might look like this:

[[See Video to Reveal this Text or Code Snippet]]

In the example above, the created_at value is a long timestamp. The goal is to automatically convert this long value into a human-readable date format when deserializing the JSON into a Java object.

Solution Approach

To convert the long timestamp into a readable date format, we will create a custom deserializer. This deserializer will handle the conversion intelligently and allow us to format the date as needed.

Step 1: Create the Plugins Class

First, define your Plugins class where you'll specify the properties and implement the custom deserialization.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Implement the CustomDateSerializer Class

Next, implement the CustomDateSerializer class that extends StdDeserializer. This is where the conversion from long to a formatted date occurs.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Create the Test Class

Finally, let's create a test class where we will utilize Jackson's ObjectMapper to parse JSON data into the Plugins class.

[[See Video to Reveal this Text or Code Snippet]]

Output Explanation

After running the test, the output will display the Plugins object with the createdAt value transformed into a readable format:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

In this guide, we successfully converted a long timestamp from JSON into a human-readable date format using Jackson in Java. Using a custom deserializer makes it flexible and easy to adapt the date format according to your needs. With this knowledge, you can enhance the readability and usability of date fields within your Java applications.

Now, you can implement this technique in your own projects and vastly improve how date information is managed and displayed!