How can you use HTTP methods in Spring Boot RESTful APIs to improve web development?

1 What are HTTP methods?

HTTP methods are the verbs of the HTTP protocol. They indicate the action that the client wants to perform on the server. For example, if you want to request a web page, you use the GET method. If you want to submit a form, you use the POST method. There are many other HTTP methods, such as PUT, PATCH, DELETE, HEAD, OPTIONS, and so on. Each one has a specific meaning and purpose in the web context. You can learn more about them in the official HTTP specification.

2 How to use GET in Spring Boot RESTful APIs?

The GET method is used to retrieve a resource from the server. For example, if you want to get a list of users, you can use a GET request to /users. In Spring Boot, you can use the @GetMapping annotation to map a method to a GET request. For example, you can write something like this:

@RestController
public class UserController {
  @Autowired
  private UserService userService;
  @GetMapping("/users")
  public List<User> getAllUsers() {
    return userService.getAllUsers();
  }
}        

This method will return a list of users in JSON format when a GET request is sent to /users. You can also use @PathVariable and @RequestParam annotations to get path and query parameters from the request.

3 How to use POST in Spring Boot RESTful APIs?

The POST method is used to create a new resource on the server. For example, if you want to create a new user, you can use a POST request to /users with the user data in the request body. In Spring Boot, you can use the @PostMapping annotation to map a method to a POST request. For example, you can write something like this:

@RestController
public class UserController {
  @Autowired
  private UserService userService;
  @PostMapping("/users")
  public User createUser(@RequestBody User user) {
    return userService.createUser(user);
  }
}        

This method will create a new user on the server and return it in JSON format when a POST request is sent to /users with the user data in the request body. You can also use @Valid and @ResponseStatus annotations to validate and set the response status code.

4 How to use PUT in Spring Boot RESTful APIs?

The PUT method is used to update a resource on the server. For example, if you want to update an existing user, you can use a PUT request to /users/{id} with the updated user data in the request body. In Spring Boot, you can use the @PutMapping annotation to map a method to a PUT request. For example, you can write something like this:

@RestController
public class UserController {
  @Autowired
  private UserService userService;
  @PutMapping("/users/{id}")
  public User updateUser(@PathVariable Long id, @RequestBody User user) {
    return userService.updateUser(id, user);
  }
}        

This method will update the user with the given id on the server and return it in JSON format when a PUT request is sent to /users/{id} with the updated user data in the request body. You can also use @Valid and @ResponseStatus annotations to validate and set the response status code.

5 How to use PATCH in Spring Boot RESTful APIs?

The PATCH method is used to partially update a resource on the server. For example, if you want to update only some fields of an existing user, you can use a PATCH request to /users/{id} with the modified user data in the request body. In Spring Boot, you can use the @PatchMapping annotation to map a method to a PATCH request. For example, you can write something like this:

@RestController
public class UserController {
  @Autowired
  private UserService userService;
  @PatchMapping("/users/{id}")
  public User patchUser(@PathVariable Long id, @RequestBody User user) {
    return userService.patchUser(id, user);
  }
}        

This method will patch the user with the given id on the server and return it in JSON format when a PATCH request is sent to /users/{id} with the modified user data in the request body. You can also use @Valid and @ResponseStatus annotations to validate and set the response status code.

6 How to use DELETE in Spring Boot RESTful APIs?

The DELETE method is used to delete a resource from the server. For example, if you want to delete an existing user, you can use a DELETE request to /users/{id}. In Spring Boot, you can use the @DeleteMapping annotation to map a method to a DELETE request. For example, you can write something like this:

@RestController
public class UserController {
  @Autowired
  private UserService userService;
  @DeleteMapping("/users/{id}")
  public void deleteUser(@PathVariable Long id) {
    userService.deleteUser(id);
  }
}        

This method will delete the user with the given id from the server and return no content when a DELETE request is sent to /users/{id}. You can also use @ResponseStatus annotation to set the response status code.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?