How to use multiple @RequestMapping annotations in spring?

java

spring

request-mapping

url-patterns

byAnton Shumikhin·Oct 2, 2024

Master @RequestMapping in Spring with both class-level and method-level annotations. Set the base path at the class level, then append specific endpoints for each method. Here's an efficient example:

@RestController
@RequestMapping("/shop")
public class ProductController {

    @GetMapping("/products")
    public List<Product> listAllProducts() {
        // Time to hit the supermarket! List 'em all.
    }

    @GetMapping("/products/{id}")
    public Product getProductDetails(@PathVariable Long id) {
        // Looking for a specific item? Gotcha covered!
    }
}

This config routes GET requests to /shop/products to list all products and to /shop/products/{id} for individual product detail ({id} being a dynamic segment here). Sweet, isn't it? @GetMapping is a shortcut for @RequestMapping(method = RequestMethod.GET), perfect for a cleaner code.

Flexible routing with multiple paths

With multiple paths in single @RequestMapping, tackle complex mapping scenarios like a pro:

@Controller
public class WelcomeController {

    @RequestMapping(value={"", "/", "/welcome"}, method=RequestMethod.GET)
    public String welcome(Map<String, Object> model) {
        // Welcome aboard! Multiple paths, same destination.
        return "welcome";
    }
}

Here, welcome() reports to duty for all three URL patterns: "", "/", and "/welcome".

Going wild with wildcard & ant-style patterns

There's more to @RequestMapping. Go wild with wildcard and ant-style paths:

@Controller
@RequestMapping("/files")
public class FileController {

    @RequestMapping("/images/**")
    public String getImages() {
        // Say cheese! Image retrieval, cat pics included.
    }
    
    @RequestMapping("/docs/*")
    public String getDocuments() {
        // Time for some serious reading. Documents, right this way.
    }
}

In this case, getImages() matches any requests starting with /files/images/, while getDocuments() matches only the paths at /files/docs/.

Specific HTTP verbs with multiple mappings

Distinguish mappings using specific HTTP methods. It's like treating verbs in English:

@Controller
public class UserController {

    @GetMapping("/users")
    public List<User> getUsers() {
        // Roll call for all users!
    }

    @PostMapping("/users")
    public User addUser(@RequestBody User user) {
        // New user announcement. Beautify with JSON.
    }
}

Here, both methods map to /users, but with different HTTP verbs (getUsers() for GET and addUser() for POST).

Best practices and pitfalls to avoid

While it's handy to map multiple URLs, watch out for overlaps and conflicts.

Avoiding conflict of mappings

Conflicting mappings can ruin your day, especially if paths overlap:

@Controller
public class AmbiguousController {

    @RequestMapping("/help")
    public String showHelp() {
        // Ambiguous mapping. It's like asking, "Doctor who?"
    }

    @RequestMapping("/help/how-to")
    public String showSpecificHelp() {
        // Another ambiguous mapping. Specifics, please?
    }
}

A request to /help/how-to might go to showHelp() instead of showSpecificHelp(). So, keep your URL patterns exclusive or logically ordered.

Router, we've a clear path now

Organize controller methods and map URLs in a way that's easy to navigate and understand. Group functionalities together, akin to a library catalog.

Double-check with testing

No misevaluation, please. Rigorously test each path, individually and collectively, to ensure correct routing. Integration testing tools (like MockMvc or RestAssured) can help you here.

Acing it with alternates

Sometimes, it's sensible to try different strategies. For instance, using configuration files to set a default view or leveraging specific HTTP method annotations gives a tidy look to your controllers.

explain-codes / Java / How to use multiple @RequestMapping annotations in spring?

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