@PathVariable for URL parameters in Spring Boot - Mini Project: Build & Apply

Using @PathVariable for URL Parameters in Spring Boot

📖 Scenario: You are building a simple Spring Boot web service that returns greetings for users based on their names provided in the URL.

🎯 Goal: Create a Spring Boot controller that uses @PathVariable to extract a user's name from the URL and return a greeting message.

📋 What You'll Learn

Create a Spring Boot controller class named GreetingController.

Add a method that handles GET requests to /greet/{name}.

Use @PathVariable to capture the name parameter from the URL.

Return a greeting message that includes the captured name.

💡 Why This Matters

🌍 Real World

Web services often need to get data from the URL path to customize responses, like user profiles or product details.

💼 Career

Understanding @PathVariable is essential for backend developers working with Spring Boot to build REST APIs.

1

Create the GreetingController class

Create a public class called GreetingController annotated with @RestController.

Spring Boot

@RestController
public class GreetingController {
    // Your code here
}

Need a hint?

Use @RestController to make the class a REST controller in Spring Boot.

2

Add a GET mapping method with @PathVariable

Inside GreetingController, add a public method called greetUser that handles GET requests to /greet/{name} using @GetMapping. The method should take a String name parameter annotated with @PathVariable.

Spring Boot

@RestController
public class GreetingController {
    // Add a method with @GetMapping("/greet/{name}") and @PathVariable String name
}

Need a hint?

Use @GetMapping("/greet/{name}") and @PathVariable String name in the method signature.

3

Implement the greeting message

In the greetUser method, return a greeting string that says "Hello, " followed by the name parameter.

Spring Boot

@RestController
public class GreetingController {
    @GetMapping("/greet/{name}")
    public String greetUser(@PathVariable String name) {
        // Return greeting message
    }
}

Need a hint?

Use string concatenation to combine "Hello, " and the name variable.

4

Add class-level request mapping

Add @RequestMapping("/api") annotation to the GreetingController class to prefix all routes with /api.

Spring Boot

// Add @RequestMapping("/api") above the class declaration
@RestController
public class GreetingController {
    @GetMapping("/greet/{name}")
    public String greetUser(@PathVariable String name) {
        return "Hello, " + name;
    }
}

Need a hint?

Use @RequestMapping("/api") above the class to add a common URL prefix.