Master 6 Essential Spring Boot Annotations for Reading Request Parameters

When developing APIs with Spring Boot, reading request parameters is a fundamental operation, and Spring Boot provides several annotations to handle different API design needs.

Below are six commonly used ways to retrieve request parameters.

@RequestParam

This is the most frequently used annotation to load parameters that appear after the ? in a URL, e.g., /user?name=didispace. Example:

@GetMapping("/user")
@ResponseBody
public User findUserByName(@RequestParam("name") String name){
    return userRepo.findByName(name);
}

@PathVariable

Used in RESTful APIs to bind variables embedded in the URL path, such as /user/1. Example:

@GetMapping("/user/{id}")
@ResponseBody
public User findUserById(@PathVariable("id") String id){
    return userRepo.findById(id);
}

@MatrixVariable

Less common; some systems use matrix variables separated by ; in the URL, e.g., /books/reviews;isbn=1234;topN=5;. Example:

@GetMapping("/books/reviews")
@ResponseBody
public List<BookReview> getBookReviews(@MatrixVariable String isbn, @MatrixVariable Integer topN){
    return bookReviewsLogic.getTopNReviewsByIsbn(isbn, topN);
}

@RequestBody

Used to bind the body of POST/PUT requests containing complex payloads. Example:

@PostMapping("/add")
public boolean addAccounts(@RequestBody List<Account> accounts) throws SQLException {
    accounts.stream().forEach(a -> {
        a.setCreatedOn(Timestamp.from(Instant.now()));
        a.setLastLogin(Timestamp.from(Instant.now()));
    });
    return notificationLogic.addAccounts(accounts);
}

@RequestHeader

Retrieves values from HTTP request headers, such as an Authorization token. Example:

@GetMapping("/user")
@ResponseBody
public List<User> getUserList(@RequestHeader("Authorization") String authToken){
    return userRepo.findAll();
}

@CookieValue

Reads cookie data, for example a SessionId. Example:

@GetMapping("/user")
@ResponseBody
public List<User> getUserList(@CookieValue(name = "SessionId") String sessionId){
    return userRepo.findAll();
}

That concludes the overview of these six Spring Boot annotations for reading request parameters.