@RequestMapping for base paths in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the base path for all requests in this controller.

Spring Boot

@RestController
[1]("/api")
public class ApiController {
    // methods here
}

Drag options to blanks, or click blank then click option'

A@GetMapping

B@RequestMapping

C@PostMapping

D@PathVariable

Attempts:

3 left

💡 Hint

Common Mistakes

Using @GetMapping or @PostMapping at class level instead of @RequestMapping.

Forgetting to add the base path in the annotation.

The @RequestMapping annotation at class level sets the base path for all methods in the controller.

2fill in blank

medium

Complete the code to map GET requests to the '/users' path under the base path.

Spring Boot

@RestController
@RequestMapping("/api")
public class UserController {
    @[1]("/users")
    public String getUsers() {
        return "";
    }
}

Drag options to blanks, or click blank then click option'

AGetMapping

BPostMapping

CRequestMapping

DDeleteMapping

Attempts:

3 left

💡 Hint

Common Mistakes

Using @PostMapping for GET requests.

Using @RequestMapping without specifying method.

Use @GetMapping to handle GET requests for the '/users' endpoint under the base path.

3fill in blank

hard

Fix the error in the code to correctly map POST requests to '/submit' under the base path.

Spring Boot

@RestController
@RequestMapping("/form")
public class FormController {
    @RequestMapping(value = "/submit", method = RequestMethod.[1])
    public String submitForm() {
        return "Submitted";
    }
}

Drag options to blanks, or click blank then click option'

AGET

BPUT

CPOST

DDELETE

Attempts:

3 left

💡 Hint

Common Mistakes

Using GET instead of POST for form submission.

Forgetting to specify the method attribute.

The method attribute should be set to RequestMethod.POST to handle POST requests.

4fill in blank

hard

Fill both blanks to create a controller with base path '/shop' and map DELETE requests to '/item'.

Spring Boot

@RestController
[1]("/shop")
public class ShopController {
    @[2]("/item")
    public String deleteItem() {
        return "Item deleted";
    }
}

Drag options to blanks, or click blank then click option'

A@RequestMapping

BGetMapping

CDeleteMapping

DPostMapping

Attempts:

3 left

💡 Hint

Common Mistakes

Using @GetMapping for DELETE requests.

Using @PostMapping at class level.

Use @RequestMapping at class level for base path and @DeleteMapping for DELETE requests.

5fill in blank

hard

Fill all three blanks to define a controller with base path '/blog', map PUT requests to '/post', and GET requests to '/posts'.

Spring Boot

@RestController
[1]("/blog")
public class BlogController {
    @[2]("/post")
    public String updatePost() {
        return "Post updated";
    }

    @[3]("/posts")
    public String getPosts() {
        return "";
    }
}

Drag options to blanks, or click blank then click option'

A@RequestMapping

BPutMapping

CGetMapping

DDeleteMapping

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing HTTP method annotations.

Forgetting to set base path with @RequestMapping.

Use @RequestMapping for base path, @PutMapping for PUT requests, and @GetMapping for GET requests.

Practice

1. What does placing @RequestMapping("/api") on a Spring Boot controller class do?

easy

A. Automatically maps all methods to the root URL /.

B. Defines the HTTP method type for all requests in the class.

C. Sets a base URL path for all request methods inside the class.

D. Disables URL mapping for the controller.

Solution

1. Step 1: Understand class-level @RequestMapping

   When @RequestMapping is placed on a controller class, it sets a base URL path prefix for all methods inside.

2. Step 2: Effect on method-level mappings

   Each method's path is appended to this base path, organizing URLs under a common root.

3. Final Answer:

   Sets a base URL path for all request methods inside the class. -> Option C

4. Quick Check:

   Class-level @RequestMapping sets base path = A [OK]

Hint: Class-level @RequestMapping sets base path prefix [OK]

Common Mistakes:

• Confusing base path with HTTP method type
• Thinking it maps all methods to root path
• Assuming it disables mapping

2. Which of the following is the correct way to set a base path /users for a Spring Boot controller using @RequestMapping?

easy

A. @RequestMapping("/users") on each method only

B. @RequestMapping(path = "/users") on the class

C. @RequestMapping(method = "users") on the class

D. @RequestMapping(basePath = "/users") on the class

Solution

1. Step 1: Check correct syntax for base path

   The correct attribute to set the path is path or directly the value in @RequestMapping. Using @RequestMapping(path = "/users") is valid and clear.

2. Step 2: Validate other options

   @RequestMapping("/users") on each method only sets path only on methods, not base path. @RequestMapping(method = "users") on the class incorrectly uses method attribute for path. @RequestMapping(basePath = "/users") on the class uses a non-existent attribute basePath.

3. Final Answer:

   @RequestMapping(path = "/users") on the class -> Option B

4. Quick Check:

   Use path attribute with leading slash [OK]

Hint: Use path="/yourBase" with leading slash on class [OK]

Common Mistakes:

• Using wrong attribute like method= for path
• Using wrong attribute name like basePath
• Setting base path only on methods

3. Given the controller class below, what is the full URL path to access the getUser() method?

@RequestMapping("/api")
public class UserController {
  @RequestMapping("/user")
  public String getUser() { return "user"; }
}

medium

A. /user

B. /user/api

C. /api

D. /api/user

Solution

1. Step 1: Identify class-level base path

   The class has @RequestMapping("/api"), so all method paths start with /api.

2. Step 2: Append method-level path

   The method getUser() has @RequestMapping("/user"), so the full path is /api + /user = /api/user.

3. Final Answer:

   /api/user -> Option D

4. Quick Check:

   Base path + method path = full URL [OK]

Hint: Combine class and method paths with slashes [OK]

Common Mistakes:

• Ignoring class-level path
• Mixing order of paths
• Missing leading slash

4. What is wrong with this controller code?

@RequestMapping("api")
public class ProductController {
  @RequestMapping("/list")
  public String listProducts() { return "products"; }
}

medium

A. Class must be annotated with @RestController or @Controller.

B. Missing leading slash in class-level @RequestMapping path.

C. Method-level @RequestMapping cannot have a path.

D. Method must return ResponseEntity, not String.

Solution

1. Step 1: Identify missing controller annotation

   The class is missing @Controller or @RestController. Without it, the class is not registered as a handler despite having @RequestMapping.

2. Step 2: Validate other options

   Method-level paths are allowed. Leading slash is optional (Spring prepends it). Returning String is valid for view names or with @ResponseBody.

3. Final Answer:

   Class must be annotated with @RestController or @Controller. -> Option A

4. Quick Check:

   Controller annotation required [OK]

Hint: Use @RestController or @Controller on controller classes [OK]

Common Mistakes:

• Missing @RestController or @Controller annotation
• Thinking method paths are disallowed
• Confusing @Controller with @RestController requirement

5. You want all endpoints in your controller to start with /shop, and inside you have a method mapped to /items. Which of these setups correctly maps the full URL /shop/items and why?

Option A:
@RequestMapping("/shop")
public class ShopController {
  @RequestMapping("/items")
  public String getItems() { return "items"; }
}

Option B:
@RequestMapping("/shop/items")
public class ShopController {
  @RequestMapping
  public String getItems() { return "items"; }
}

Option C:
@RequestMapping
public class ShopController {
  @RequestMapping("/shop/items")
  public String getItems() { return "items"; }
}

Option D:
@RequestMapping(shop)
public class ShopController {
  @RequestMapping(items)
  public String getItems() { return "items"; }
}

hard

A. Option A correctly sets base path and method path with leading slashes.

B. Option B sets full path on class, method has no path, works fine.

C. Option C sets full path on method only, class has no base path.

D. Option D misses leading slashes, so paths are invalid.

Solution

1. Step 1: Identify the correct configuration

   The setup with class-level @RequestMapping("/shop") and method-level @RequestMapping("/items") combines to /shop/items with full syntax validity (parentheses, quotes, leading slashes).

2. Step 2: Examine incorrect configurations

   The full class path setup lacks parentheses on method @RequestMapping (syntax error). The full method path setup lacks parentheses on class @RequestMapping (syntax error). The no-slash setup lacks quotes on shop and items (syntax error).

3. Final Answer:

   Option A correctly sets base path and method path with leading slashes. -> Option A

4. Quick Check:

   Base path + method path + valid syntax = full URL [OK]

Hint: Use leading slashes on class and method paths for clarity [OK]

Common Mistakes:

• Missing parentheses in @RequestMapping
• Missing quotes around path values
• Omitting leading slashes on paths