Скачать или смотреть How to Add a JSON Object to an Existing JSON File in Java

Learn how to effectively `merge` two JSON objects in Java, allowing you to add new data without losing existing information.
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This video is based on the question https://stackoverflow.com/q/67582767/ asked by the user 'Vish' ( https://stackoverflow.com/u/14785853/ ) and on the answer https://stackoverflow.com/a/67582924/ provided by the user 'Kashif Mehmood' ( https://stackoverflow.com/u/10669847/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Add a JSON Object to an Existing JSON File in Java

JSON (JavaScript Object Notation) is a popular data format for storing and exchanging information. As a Java developer, you may encounter situations where you need to add new data to an existing JSON file. Whether it's appending user information, updating configurations, or merging datasets, this guide will provide you with a step-by-step solution to add a JSON object to an existing JSON file.

Understanding the Problem

Suppose you have an existing JSON file named demo.json, containing data about students. Here is how the file looks:

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

Now, you want to add a new employee object to this existing JSON structure, which means your desired outcome is to have a merged JSON that looks like this:

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

Step-by-Step Solution

To achieve this, you will need to follow these steps:

Step 1: Include Required Libraries

Ensure you have the required library for handling JSON in Java. One common library is org.json. You can include it in your project using Maven or by downloading it directly.

Step 2: Read the Existing JSON File

You will need to read the existing demo.json file into a JSONObject. Here's how you can do that:

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

Step 3: Create the New JSON Object

Next, create a new JSON object for the employee information you want to add:

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

Step 4: Merge the JSON Objects

To merge the two JSON objects, you can use the following code snippet:

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

Step 5: Write the Merged JSON Back to the File

After merging, you will want to write the updated JSON back into the demo.json file. To do this, you can use the following code:

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

The toString(4) method will format your JSON for better readability with an indentation of 4 spaces.

Conclusion

Combining JSON objects may seem daunting at first, but with the right tools and libraries, it can be straightforward. By following these steps, you can successfully add new information—like employee details—to your existing JSON files without losing any existing data.

Now you can manage your JSON data more efficiently in your Java applications. Happy coding!