Each annotation is meant to handle the relevant incoming request method type, as seen by the naming convention. It may appear that the @RequestMapping and @GetMapping methods are the same, but they are not.
When it comes to @RequestMapping,
it will demonstrate that it is used to generic request handler where we may
use with GET, POST, PUT, or any other request methods utilizing the method
attribute in Spring 4.3 new mapping annotations.
First, have a look at what is @RequestMapping and what our use cases are with a simple example. @RequestMapping is one of the most common annotations used in Spring Web applications. This annotation maps HTTP requests to handler methods of MVC and REST controllers.
The method is run every time an end-user makes an HTTP request. The mapping can also be done at the method or class level.
From here, the /student is assigned on the class level. And each method has separate mappings and this allows to have a prefix before creating the mapping.
The method attribute in the request method allows you to narrow down the request method to a specific request method. (GET, POST, PUT, DELETE, etc)
The @ReqeustMapping annotation allows you to rely on the path variables to showcase a specific student, profile, grade, etc. as an example student/IT175644 this allows getting the specific student.
Many applications rely on request parameters to alter the state of the page. You can also use @RequestParam annotation to bind a request parameter to a variable.
@GetMapping - shortcut for @RequestMapping(method = RequestMethod.GET)
In the below example, the @GetMapping annotation mapping HTTP GET "/employees" and "/employees/{id}" requests onto specific handler methods getAllEmployees and getEmployeeById:
The @RequestMapping annotation is used to map web requests to specific handler classes and functions. This annotation's key advantage is that it may be used on both the controller class and methods.
So this is all about the difference between @RequestMapping and @GetMapping in Spring MVC and REST. @RequestMapping is a general purpose request mapping annotation which can be used to map any HTTP methods like GET, POST, and PUT and used at the class level while @GetMapping is a specialized annotation which is used to map GET request and used to connect the methods. I
First, have a look at what is @RequestMapping and what our use cases are with a simple example. @RequestMapping is one of the most common annotations used in Spring Web applications. This annotation maps HTTP requests to handler methods of MVC and REST controllers.
1. What is @RequestMapping Annotation? Example
This is one of the basic annotations in Spring that maps HTTP requests with methods. This is used to map the request into the specific method in Spring.@RequestMapping("/")
public void requestMapping() {
return "Hello !";
}
The method is run every time an end-user makes an HTTP request. The mapping can also be done at the method or class level.
@RequestMapping("/student")
public class AdminController() {
@RequestMapping("/addstudent")
public String addStudent() {
return "addStudent.html";
}
@RequestMapping("/getallstudent")
public String getStudents() {
return "getStudent.html";
}
}
From here, the /student is assigned on the class level. And each method has separate mappings and this allows to have a prefix before creating the mapping.
The method attribute in the request method allows you to narrow down the request method to a specific request method. (GET, POST, PUT, DELETE, etc)
@Autowired
StudentRepository studentRepository;
@RequestMapping(value = "/addStudent", method = RequestMethod.POST)
public String addStudent(@ModelAttribute("student") Student student) {
studentRepository.save(student);
}
The @ReqeustMapping annotation allows you to rely on the path variables to showcase a specific student, profile, grade, etc. as an example student/IT175644 this allows getting the specific student.
@Autowired
StudentRepository studentRepository;
@RequestMapping("/viewStudent/{studentId}")
public String viewStudent(@PathVariable int studentId, Model model) {
Student student = studentRepository.getStudentById(studentId);
model.addAttribute("student", student);
return "viewStudent";
}
Many applications rely on request parameters to alter the state of the page. You can also use @RequestParam annotation to bind a request parameter to a variable.
@RequestMapping("/login")
public String login(@RequestParam(value = "error", required = false) String error,
@RequestParam(value = "logout", required = false) String logout, Model model) {
if (error != null) {
model.addAttribute("error", "Wrong username or password!");
}
if (logout != null) {
model.addAttribute("msg", "You have successfully logged out!");
}
return "login";
}
2. What is @GetMapping Annotation? Example
HTTP GET requests are mapped to appropriate handler methods using the Spring @GetMapping annotation. The @GetMapping annotation assigns specified handler methods to HTTP GET requests. @RequestMapping(method = RequestMethod.GET) is a constructed annotation that serves as a shorthand for @RequestMapping(method = RequestMethod.GET).@GetMapping - shortcut for @RequestMapping(method = RequestMethod.GET)
In the below example, the @GetMapping annotation mapping HTTP GET "/employees" and "/employees/{id}" requests onto specific handler methods getAllEmployees and getEmployeeById:
@Autowired
StudentRepository studentRepository;
@GetMapping("/students/{id}")
public ResponseEntity < Students > getEmployeeById(
@PathVariable(value = "id") Long studentId)
throws ResourceNotFoundException {
Students student = studentRepository.findById(studentId)
.orElseThrow(() - > new ResourceNotFoundException("Student not found
for this id :: " + studentId));
return ResponseEntity.ok().body(Students);
}
Difference between @RequestMapping and @GetMapping in Spring MVC?
With sprint Spring 4.3. and up things have changed. Now can use the @GetMapping methods that will handle the HTTP requests. The class-level @RequestMapping specification is refined with the (method-level)@GetMapping annotation.- @RequestMapping is a class level
- @GetMapping is a method-level
The @RequestMapping annotation is used to map web requests to specific handler classes and functions. This annotation's key advantage is that it may be used on both the controller class and methods.
The @RequestMapping is typically
thought of as a class-level annotation. With the help of method level, get
mapping, @Requestmapping is
fine-tuned.
It is always advised to be specific while declaring @RequestMapping on the controller methods as in most mapping handler classes, @Getmapping is not used. This feature distinguishes the @Getmapping and @RequestMapping annotations.
It is always advised to be specific while declaring @RequestMapping on the controller methods as in most mapping handler classes, @Getmapping is not used. This feature distinguishes the @Getmapping and @RequestMapping annotations.
It's an annotation that serves as a shortcut for the
@Requestmapping annotation.
Request handler pathways are mapped to specified handler methods. In
comparison to @Requestmapping,
there are fewer lines of code.
@Getmapping("/peson/{personId}")
By default, the entire requests are assumed to be originated from the HTTP
Get type.
This is how Craig Walls describe the difference between @RequestMapping and @GetMapping in Spring in Action, Fifth Edition.
This is how Craig Walls describe the difference between @RequestMapping and @GetMapping in Spring in Action, Fifth Edition.
So this is all about the difference between @RequestMapping and @GetMapping in Spring MVC and REST. @RequestMapping is a general purpose request mapping annotation which can be used to map any HTTP methods like GET, POST, and PUT and used at the class level while @GetMapping is a specialized annotation which is used to map GET request and used to connect the methods. I
f you are mapping GET request then its better to use @GetMapping annotation rather than @RequestMapping for better readability and conciseness in code.
This is also an important Spring MVC interview
question to knowing how and when to use both RequestMapping and GetMapping
is crucial for Java developers.
See you in the next tutorial with a more interesting topic.
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1 comment :
THis question was asked to me while interviewing for JP Morgan for Analyst role. They also asked about @PostMapping and which method should be better to handle large requests?
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