How many ways we can get parameter value in spring boot controller? - 4

Roman Sarker 7/10/2024 03:57:00 PM
In Spring Boot, we can get parameter values in a controller method in various ways depending on the type of parameter and its source. 
Java Spring Boot Logo


Here are several common ways to retrieve parameter values in spring boot controller method:
  1. Path Variables : @PathVariable
  2. Request Parameters : @RequestParam
  3. Request Body : @RequestBody
  4. Request Headers : @RequestHeader
  5. Cookie Values : @CookieValue
  6. Matrix Variables : @MatrixVariable
  7. Form Data : @ModelAttribute
  8. File Uploads : @RequestParam with MultipartFile
  9. Servlet API : HttpServletRequest and HttpServletResponse
  10. Session Attributes : HttpSession
  11. Spring Security Principal : Principal

1. Path Variables
Path variables are part of the URL path.
@GetMapping("/user/{id}")
public ResponseEntity<User> getUserById(@PathVariable("id") Long id) {
    // Use the id parameter
}

2. Request Parameters
Request parameters are typically used in query strings. Like getting employee's information with employee ID numbers.
@GetMapping("/search")
public ResponseEntity<List<User>> searchUsers(@RequestParam("id") String empId) {
    // Use the empId parameter
}

3. Request Body
Request bodies are used to send complex data in a request. Typically receive JSON data to save/update.
@PostMapping("/user")
public ResponseEntity<User> createUser(@RequestBody User user) {
    // Use the user object
}

4. Request Headers
Request headers are additional information sent with the request. Like Authorization key or Token.
@GetMapping("/user")
public ResponseEntity<User> getUser(@RequestHeader("Authorization") String authHeader) {
    // Use the authHeader
}

5. Cookie Values
Cookies can be used to store small pieces of data on the client side.
@GetMapping("/cookie")
public ResponseEntity<String> getCookieValue(@CookieValue("sessionId") String sessionId) {
    // Use the sessionId cookie
}

6. Matrix Variables
Matrix variables are a way to pass parameters in the path segment.
@GetMapping("/user/{id}")
public ResponseEntity<User> getUserById(@PathVariable("id") Long id, @MatrixVariable("name") String name) {
    // Use the id and name parameters
}

7. Form Data
Form data is used for form submissions. Specially use for Java EE Applications.
@PostMapping("/submit")
public ResponseEntity<String> submitForm(@ModelAttribute Form form) {
    // Use the form data
}

8. File Uploads
File uploads are typically used for uploading files.
@PostMapping("/upload")
public ResponseEntity<String> handleFileUpload(@RequestParam("file") MultipartFile file) {
    // Use the uploaded file
}

9. Servlet API
we can access raw HTTP request and response objects.
@GetMapping("/servlet")
public ResponseEntity<String> servletApiExample(HttpServletRequest request, HttpServletResponse response) {
    String param = request.getParameter("param");
    // Use the request and response objects
}

10. Session Attributes
Session attributes are stored in the session scope.
@GetMapping("/session")
public ResponseEntity<String> sessionExample(HttpSession session) {
    String attribute = (String) session.getAttribute("attribute");
    // Use the session attribute
}

11. Spring Security Principal
we can access the authenticated user details.
@GetMapping("/principal")
public ResponseEntity<String> principalExample(Principal principal) {
    String username = principal.getName();
    // Use the principal
}

Using these annotations and objects, we can handle a wide variety of request parameters and data in our Spring Boot controller methods. In the next blog, we will see practically the most useful ways to get parameters.


Tags
Roman Sarker

Posted by Roman Sarker

Post a Comment

0 Comments