Скачать или смотреть How to Get the Value of Query Param Array in Spring Boot

Learn how to effectively retrieve values from query parameters in Spring Boot, specifically handling array parameters.
---
This video is based on the question https://stackoverflow.com/q/72990251/ asked by the user 'WISHY' ( https://stackoverflow.com/u/2569793/ ) and on the answer https://stackoverflow.com/a/72990895/ provided by the user 'milkdove' ( https://stackoverflow.com/u/19205249/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to get value of query param array in spring boot?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Get the Value of Query Param Array in Spring Boot

Handling query parameters is an essential part of web development, especially when working with frameworks like Spring Boot. One common scenario developers encounter is needing to access array values from query parameters. In this post, we will address a common issue: How to correctly retrieve values from a query parameter array in Spring Boot.

The Problem

Imagine you have a URL that looks like this:

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

In this case, you want to extract the value of ot-replace[0] which is kin43 and possibly other values like value2, value3, etc. However, when trying to retrieve these values in your Spring Boot controller, you find that they consistently return null, even when using several methods to capture them.

Your controller code might look something like this:

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

or like this:

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

Both approaches result in null, leaving you baffled about what could be going wrong in your implementation.

The Solution

To successfully retrieve an array of values from a query parameter, it's important to format the URL correctly. Here’s how you can do it:

Correct URL Formatting

Instead of using the square brackets in your query parameter, modify your URL as follows:

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

Explanation

Comma-Separated Values: By using commas to separate the values in the parameter, Spring Boot is able to understand that ot-replace is intended to be an array.

Array Binding: Now, when you use the same annotations in your controller, Spring Boot will bind the values from the query parameter into an array.

Example of Working Code

Here is a simplified version of how this can be implemented in your controller:

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

Key Takeaways

Make sure to format your query parameter without using indexed notation (e.g., [0]).

Use a comma to separate multiple values in the same query parameter.

Ensure that your controller's @ RequestParam correctly matches the parameter name and is set to capture multiple values.

By following these steps, you should be able to easily extract array values from query parameters in your Spring Boot application. Happy coding!