What is the @PutMapping annotation in Spring Boot, its principle, and how to use it

In Spring Boot, @PutMapping is an annotation that maps HTTP PUT requests to specified processing methods. This article will introduce the principle of @PutMapping and how to use it in Spring Boot.

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The principle of @PutMapping annotation

In RESTful APIs, PUT requests are commonly used to update resources. For example, we can use a PUT request to update a user's information to the server. In Spring Boot, we can use the @PutMapping annotation to map PUT requests to specified processing methods.

The @PutMapping annotation uses the common configuration elements of the @RequestMapping annotation, such as method, params, headers, consumes, and produces. It also supports a value attribute to specify the request path of the processing method.

When a PUT request arrives at the server, Spring Boot will match the processing method marked by the @PutMapping annotation according to the request path and request parameters. If a matching method is found, Spring Boot will call this method to process the request and return the result.

How to use @PutMapping annotation

In Spring Boot, using @PutMapping annotation is very simple. We just need to add @PutMapping annotation on a processing method. For example:

@RestController
@RequestMapping("/users")
public class UserController {
    
    

    @PutMapping("/{id}")
    public ResponseEntity<User> updateUser(@PathVariable Long id, @RequestBody User user) {
    
    
        // Update the user with the given ID
        return ResponseEntity.ok(user);
    }

}

In the above code, we created a class called UserController and added @RestController and @RequestMapping annotations on it. We define a processing method called updateUser in this class and add the @PutMapping annotation to it. This method accepts two parameters: an id of type Long, representing the user ID to be updated, and a user of type User, representing the user information to be updated.

In the updateUser method, we can update user information according to id and user, and return the updated user information. In this example, we simply return the updated user information, use the ResponseEntity.ok() method to package it into an HTTP response and return it to the client.

In addition to the value attribute, the @PutMapping annotation supports other attributes such as consumes and produces. These properties give us more fine-grained control over the media type of the request and the media type of the response. For example:

@RestController
@RequestMapping("/users")
public class UserController {
    
    

    @PutMapping(
      value = "/{id}",
      consumes = MediaType.APPLICATION_JSON_VALUE,
      produces = MediaType.APPLICATION_JSON_VALUE
    )
    public ResponseEntity<User> updateUser(@PathVariable Long id, @RequestBody User user) {
    
    
        // Update the user with the given ID
        return ResponseEntity.ok(user);
    }

}

In the above code, we specify the user ID to be updated in the @PutMapping annotation, use the consumes attribute to specify the requested media type as JSON, and use the produces attribute to specify the response media type as JSON.

Summarize

In this article, we introduced the @PutMapping annotation in Spring Boot. It can map HTTP PUT requests to specified processing methods. We also covered how the @PutMapping annotation works and how to use it in Spring Boot.

Using the @PutMapping annotation can help us process PUT requests more conveniently and reduce the workload of manual configuration. Of course, we need to pay attention to some details when using the @PutMapping annotation. For example, ensure that the parameter types of the request path, request parameters, and processing methods are correct to avoid matching failures. At the same time, when using the consumes and produces attributes, it also needs to be adjusted and optimized according to the actual situation.

Finally, if you want to learn more about other annotations and features of Spring Boot, you can refer to official documents or other related materials, which will help you better understand and apply Spring Boot. Here is a complete code example:

@RestController
@RequestMapping("/users")
public class UserController {
    
    

    @PutMapping(
      value = "/{id}",
      consumes = MediaType.APPLICATION_JSON_VALUE,
      produces =MediaType.APPLICATION_JSON_VALUE
    )
    public ResponseEntity<User> updateUser(@PathVariable Long id, @RequestBody User user) {
    
    
        // Update the user with the given ID
        return ResponseEntity.ok(user);
    }

}