![\"Stereotype](\"https:\/\/onlinecodinghelp.com\/wp-content\/uploads\/2023\/10\/Mind-map-1024x811.jpeg\")
<\/figure>\n<\/figure>\n\n\n\n@<\/strong>Compo<\/b>nent:<\/strong> – It is a class level annotation. It is used to mark a Java class as a bean. A Java class annotated with @Component<\/strong> is found during the class path. The spring framework pick it up and configure it in the application context as a Spring Bean<\/strong>. <\/p>\n\n\n\n @<\/strong>Configu<\/b>ration: –<\/strong> It is a class level annotation. The class annoted with @Configuration<\/strong> used by spring Containers a source of bean definitions.<\/p>\n\n\n\n @<\/strong>Repository: –<\/b>It is a class level annotation. @Repository<\/strong> annotation is a specialization of @Component<\/strong> annotation which is used to indicate that the class provides the mechanism for storage, retrieval, update, delete and search operation on objects. The repository is a DAOs <\/strong>(Data Access Object) that access the database directly. Though it is a specialization of @Component<\/strong> annotation, so Spring Repository classes are autodetected by spring framework through classpath scanning. <\/p>\n\n\n\n @<\/strong>Service:<\/b> – It is class level annotation. It is also a specialization of @Component Annotation<\/strong> like the @Repository Annotation<\/strong>. It tells the spring that class contains the business logic<\/strong>.<\/p>\n\n\n\n @Controller: –<\/strong> It is class level annotation. it is also specialization of @Component<\/strong> Annotation<\/strong>. It marks a class as a web request handler. It is often used to serve web pages. By default, it returns as String that indicates which route to redirect. It is mostly used with @RequestMapping<\/strong> annotation.<\/p>\n\n\n\n @<\/strong>RestController: –<\/b> It can be considered as a combination of @Controller<\/strong> and @ResponseBody<\/strong> annotations. The @RestController<\/strong> annotation is itself annoted with @ResponseBody<\/strong> annotation. It eliminates the need for annoting each method with @<\/strong>Respons<\/b>eBody.<\/strong><\/p>\n\n\n\n Spring Boot Annotations<\/strong><\/p>\n\n\n\n @SpringBootApplication<\/strong> :- @SpringBootApplication<\/strong> annotation is combination of three annotations @EnableAutoConfiguration<\/strong>, @ComponentScan<\/strong>, and @SpringBootConfiguration<\/strong>. <\/p>\n\n\n\n <\/p>\n\n\n\n @<\/strong>ComponentSc<\/b>an: –<\/strong> The component scan annotation is scan all the classes in package and its sub packages and create beans if the class is annotated with stereotype annotations. <\/p>\n\n\n\n <\/p>\n\n\n\n Spring MVC And REST Annotations<\/strong><\/p>\n\n\n\n @RequestMapping :-<\/strong> It Is used to map the web requests . It has many optional elements like consumes , header , method , name , params , path , produces , and values . We use it with the class as well as the method.<\/p>\n\n\n\n @GetMapping :-<\/strong> It maps the HTTP GET<\/strong> requests on the specific handle method . It is used for data RETRIEVE<\/strong>.<\/p>\n\n\n\n @<\/strong>PostMapping: –<\/b> It maps the HTTP POST<\/strong> request on the specific handler method. It is used for ADD<\/strong>.<\/p>\n\n\n\n @PutMapping: –<\/strong>It maps the HTTP PUT<\/strong> request on the specific handler method. It is used for UPDATE<\/strong>.<\/p>\n\n\n\n @<\/strong>DeleteMapping: –<\/b> It maps the HTTP DELETE<\/strong> requests on the specific handler method. It is used for D<\/b>ELETE.<\/strong><\/p>\n\n\n\n @RequestBody: –<\/strong> It is used to bind HTTP<\/strong> request with an object in a method parameter. Internally it uses HTTP<\/strong> Message Converter<\/strong> to convert the body of the request. When we annotate a method parameter with @<\/strong>Request<\/b>Body,<\/strong> the spring framework binds the incoming HTTP<\/strong> request to the body parameters.<\/p>\n\n\n\n @ResponseBody: –<\/strong>It binds the method return value to the response body. It tells the spring boot framework to serialize a return an object into JSON<\/strong> and XML<\/strong> format.<\/p>\n\n\n\n @PathVariable: –<\/strong> It is used to extract the values from the URL<\/strong>. It is most suitable for the REST<\/strong>ful web service, where the URL<\/strong> contains a path variable. We can define multiple @PathVariable<\/strong> in a method.<\/p>\n\n\n\n @RequestParam<\/strong>: – It is used to extract the Query<\/strong> parameters from the URL<\/strong>. It is also Known as Query<\/strong> parameter. It can specify default values if the query parameter is not present in the URL<\/strong>.<\/p>\n\n\n\n @RestController: –<\/strong> It can be considered as a combination of @Controller<\/strong> and @ResponseBody<\/strong> annotations. The @RestController<\/strong> annotation is itself annoted with the @<\/strong>ResponseBod<\/b>y <\/strong>annotation. It eliminates the need for annoting each method with @ResponseBody<\/strong>.<\/p>\n\n\n\n <\/p>\n\n\n\n @RequestMapping And Its Attributes<\/strong><\/p>\n\n\n\n The @RequestMapping<\/strong> annotation is a core annotation in Spring Boot that is used to map a specific HTTP<\/strong> request method to a specific Java method in web application. This means that when a request is sent to the web application, Spring Boot will use the @RequestMapping<\/strong> annotation to determine which Java method should handle the request.<\/p>\n\n\n\n The @RequestMapping<\/strong> annotation can be used to specify the request type like GET, POST, PUT, DELETE <\/strong>this will handle the request. for example, if you want to handle GET <\/strong>request to the “\/contact<\/strong>” URL path, there is two ways to handle specific request you can use @RequestMapping (value = “\/contact”, method=RequestMethod.GET<\/em>)<\/strong> this will tell Spring Boot that this Java method should handle GET<\/strong> request to the “\/contact<\/strong>” path. You can also use @GetMapping (value = “\/contact”)<\/strong> both annotation handle GET<\/strong> request. In @GetMapping<\/strong> annotation there is @RequestMapping<\/strong> annotation which is working Internally like this @RequestMapping (method = RequestMethod.GET<\/em>)<\/strong>.<\/p>\n\n\n\n The @RequestMapping<\/strong> annotation is commonly used in RESTful web services to map HTTP<\/strong> request methods to specific Java methods that handle those requests. For example<\/strong>, a GET<\/strong> request to the \/contact<\/strong> URL path can be used to retrieve the list of contact from a database, while POST<\/strong> request to the same URL path can be used to create new contact in the database. Additionally, Spring Boot provides other related annotations, such as @GetMapping,<\/strong> @PostMapping, @PutMapping, @<\/strong>DeleteMappi<\/b>ng<\/strong>. This annotation has specific HTTP<\/strong> methods in @RequestMapping<\/strong>.<\/p>\n\n\n\n Attributes of @RequestMapping Annotation<\/strong><\/p>\n\n\n\n When using the @RequestMapping<\/strong> annotation at method-level in Spring Boot application, the annotation provides a number of attributes that can be used to customize the behavior of request mapping. Some of the commonly used attributes are: <\/p>\n\n\n\n -><\/strong>valu<\/b>e:<\/strong> This attribute specifies the URL path that the request mapping should apply to. for example, @RequestMapping(“\/contact”) <\/strong>would match any request with the URL path “\/contact”<\/strong>. <\/p>\n\n\n\n ->method<\/strong>: This method specifies the HTTP method that the request mapping should apply to. It can take a RequestMethod<\/strong> value such as GET, POST, PUT, DELETE, etc. For example, @RequestMapping (values=”\/contact”, method=RequestMethod.GET)<\/strong> would match any GET request with URL path “\/contact”<\/strong>. <\/p>\n\n\n\n ->params:<\/strong> This attribute specifies the request parameter conditions that should be met for the request mapping to be considered a match. For example, @RequestMapping (value = “\/contact”, params = “id<\/strong>“)<\/b> would match any request with URL path of “\/contact”<\/strong> that has an “id”<\/strong> parameter.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n![\"\"](\"https:\/\/onlinecodinghelp.com\/wp-content\/uploads\/2023\/10\/Blank-board-1-1024x787.jpeg\"){kind=spacer}
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