SpringBoot common annotations

2024-07-12

@RestController

It is the coupling of @ResponseBody and @Controller.

@Controller indicates that the class is a controller, and @ResponseBody indicates that the object returned by the controller's method is used directly as the body of the HTTP response, rather than as a view.

Comments written in parameter lists

@PathVariable：

@GetMapping("/users/{userId}")

Used to extract variables from URL templates.
When you define a RESTful API, you can use this to capture path parameters defined in the URL.
For example, if you have a URL pattern/users/{userId}, and the requested URL is/users/123,So123can be used asuserIdParameters are passed to the controller method.
Usually with@RequestMappingor@GetMapping、@PostMappingUsed together with other annotations.


@GetMapping("/users/{userId}")
public User getUserById(@PathVariable("userId") int userId) { // 根据userId获取用户信息 }

@RequestParam：

Used to extract values from the request's query parameters.
It allows you to access the query string portion of the URL, such as?name=value。
Even if no parameters are specified in the request, you can userequired=falseAttributes are set to be optional, or bydefaultValueThe property provides a default value.
Usually with@RequestMappingor@GetMapping、@PostMappingUsed together with other annotations.


@GetMapping("/search") 
public List<User> searchUsers(@RequestParam(value = "name", required = false) String name) { // 根据提供的name参数搜索用户 }

@RequestBody

@RequestBodyAllows you to automatically convert (through appropriate converters such as Jackson or JAXB) the request body (JSON, XML, etc.) sent by the client and bind it to an object.
When using@RequestBodyWhen calling HttpChannel("application/json", "application/json"); , the request sent by the client is expected to have a non-empty request body. If the request body is empty, Spring will throw an exception.
Used to map the body of an HTTP request to the parameters of a controller method.
Mainly used for requests such as POST, PUT, and PATCH, which usually require the client to submit data to create or update resources


@PostMapping("/users")
public ResponseEntity<?> addUser(@RequestBody User user) {
    // 将接收到的User对象保存到数据库
    userService.addUser(user);
    return ResponseEntity.ok().build();
}

Technology Sharing