@PathVariable for URL parameters in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @PathVariable annotation in Spring Boot?

The @PathVariable annotation is used to extract values from the URL path and bind them to method parameters in a controller. It helps get dynamic parts of the URL as variables.

beginner

How do you define a method parameter to capture a URL segment named id using @PathVariable?

You add @PathVariable("id") before the method parameter. For example: public String getUser(@PathVariable("id") String id).

intermediate

Can @PathVariable be used without specifying the variable name inside the parentheses? When?

Yes, if the method parameter name matches the path variable name in the URL template, you can omit the name in @PathVariable. For example, if the URL is /user/{id} and the parameter is String id, just use @PathVariable String id.

beginner

What happens if a URL does not contain the expected path variable when using @PathVariable?

Spring Boot will return a 404 error because the URL does not match the expected pattern that includes the path variable.

intermediate

How can you handle multiple @PathVariable parameters in a single controller method?

You can add multiple parameters each annotated with @PathVariable matching the URL template. For example: @GetMapping("/order/{orderId}/item/{itemId}") with method parameters @PathVariable String orderId, @PathVariable String itemId.

What does @PathVariable do in a Spring Boot controller?

A Reads query parameters from the URL

B Extracts values from the URL path and binds them to method parameters

C Handles form data submission

D Defines the HTTP method type

@PathVariable extracts dynamic parts of the URL path, not query parameters or form data.

Given the URL /user/42 and mapping @GetMapping("/user/{id}"), how do you capture 42 in the method?

A Use <code>@PathVariable("id") String id</code> as a parameter

B Use <code>@RequestParam("id") String id</code>

C Use <code>@RequestBody String id</code>

D Use <code>@CookieValue("id") String id</code>

The @PathVariable annotation captures the value from the URL path segment.

If the method parameter name matches the path variable name, how can you simplify @PathVariable usage?

A Omit the variable name inside <code>@PathVariable</code>

B Remove <code>@PathVariable</code> entirely

C Use <code>@RequestParam</code> instead

D Use <code>@PathVariable("differentName")</code>

You can omit the name if the parameter name matches the path variable name exactly.

What HTTP status code does Spring Boot return if a required @PathVariable is missing in the URL?

A 500 Internal Server Error

B 400 Bad Request

C 404 Not Found

D 200 OK

Spring Boot returns 404 because the URL pattern does not match the expected route.

How do you handle multiple path variables in a URL like /order/{orderId}/item/{itemId}?

A Use <code>@RequestBody</code> to get both variables

B Use a single <code>@PathVariable</code> with a list

C Use <code>@RequestParam</code> for both variables

D Add multiple <code>@PathVariable</code> parameters matching each variable

Each path variable needs its own @PathVariable parameter in the method.

Explain how @PathVariable works in Spring Boot and how you use it to get data from the URL.

Think about how you get the 'id' from a URL like /user/123.

Describe what happens if the URL does not include the expected path variable when using @PathVariable in a controller.

Consider what happens when you visit a URL missing a required part.