Spring Boot - Query Parameters

👋 Introduction

In previous article Getting Started with Spring Boot: Your First "Hello, World!" REST API, we created a simple Spring Boot Rest API which returns a string. Now let’s take things a little further and make our application little dynamic by adding query parameters to our HTTP Request.

🛠️ Step 1: Create a Spring Boot Project

🔧 Configuration:

• Project: Maven

• Language: Java

• Spring Boot: (Use the latest stable version)

• Dependencies: Spring Web

• Package name: com.queryparams or whatever you like.

The configuration should look like this

Click Generate, unzip the downloaded file, and open it in your favourite IDE (IntelliJ IDEA, Eclipse, VS Code). I prefer to use IntelliJ IDEA.

📁 Step 2: Understand the Project Structure

src
└── main
├── java
│ └── com.queryparams
│ ├── QueryParamsApplication.java
└── resources
├── application.properties

• We'll now create a QueryPatamsController.java to handle HTTP requests.

👨‍💻 Step 3: Create the Controller

package com.amanvw;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class QueryParamsController {

    @GetMapping("/hello")
    public String sayHello(@RequestParam String name) {
        return "Hello, " + name + "!";
    }
}

• @RequestParam is the new annotation we introduced here. This annotation is used to extract query parameters, form parameters or any URL parameters from a HTTP Request and bind them to a controller method parameter.

• So, in our HTTP request when we provide ?name=something, spring boot will bind it with the sayHello method parameter — name.

• Let’s try it out!

▶️ Step 4: Run the Application

To run the application, you can either

📦 Use Maven:

./mvnw spring-boot:run

🧠 Or use your IDE:

Right-click on QueryParamsApplication.java → Run.

You’ll see logs ending with:

Tomcat started on port(s): 8080 (http)

🌐 Step 5: Test the Endpoint

Open your browser or Postman and go to:

http://localhost:8080/hello?name=Aman

✅ Output:

Hello, Aman!

Now, try not providing the query parameter and see what happens. You’ll see an error page.

🧠 Understand @RequestParam

• When you provide @RequestParam String name, you implicitly specify that name is required parameter.

• To make it not-required use, @RequestParam(required = false) String name

• Also, you can have a different query parameter names in your HTTP Request and the method parameters — @RequestParam(required = false, name = "name") String firstName

Let’s try this out by adding following method in our QueryParamsController

    @GetMapping("/hello-address")
    public String sayHelloAddress(@RequestParam String name,
                                  @RequestParam(required = false, name = "address") String place) {
        if (place == null) {
            return "Hello, " + name + "!";
        }
        return "Hello, " + name + " from " + place + "!";
    }

Stop and start the application again.

Open your browser or Postman and go to:

http://localhost:8080/hello-address?name=Aman&address=India

✅ Output:

Hello, Aman from India!

Since, address is optional:

http://localhost:8080/hello-address?name=Aman

✅ Output:

Hello, Aman!

🔚 Conclusion

You just created a simple Spring Boot application that accepts different query parameters and renders response based on those.

You can find the complete code here: GitHub - AmanVW

Stay tuned for the next part in the series!

© Aman Walke