{"id":300,"date":"2025-06-03T13:00:00","date_gmt":"2025-06-03T13:00:00","guid":{"rendered":"https:\/\/springmasteryhub.com\/?p=300"},"modified":"2025-04-30T14:54:09","modified_gmt":"2025-04-30T14:54:09","slug":"how-to-use-controller-in-spring","status":"publish","type":"post","link":"https:\/\/springmasteryhub.com\/?p=300","title":{"rendered":"How to Use @Controller in Spring"},"content":{"rendered":"\n

What is?<\/h2>\n\n\n\n

This class-level annotation tells Spring that your class is a controller. A controller is an entry point for a web application. This allows you to define a path to communicate with your backend using REST methods or by serving and responding html forms.<\/p>\n\n\n\n

This more general annotation allows your controller to serve REST endpoints and webpage content, which is very common in the MVC pattern.<\/p>\n\n\n\n

Why is this important<\/h2>\n\n\n\n

This annotation is what allows your front end to communicate with the backend, allowing you to define routes, pages, dynamic content, etc. If you are working with web applications, this annotation is one of the most important ones.<\/p>\n\n\n\n

How to use @Controller<\/h2>\n\n\n\n

Defining a controller class<\/h3>\n\n\n\n
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import<\/span> org.springframework.stereotype.Controller;<\/span><\/span>\n<\/span>\n@<\/span>Controller<\/span><\/span>\npublic<\/span> <\/span>class<\/span> <\/span>MyController<\/span> {<\/span><\/span>\n    <\/span>\/\/ controller methods go here<\/span><\/span>\n}<\/span><\/span>\n<\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
Defining an endpoint and its respective HTTP method<\/h3>\n\n\n\n
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import<\/span> org.springframework.stereotype.Controller;<\/span><\/span>\nimport<\/span> org.springframework.web.bind.annotation.GetMapping;<\/span><\/span>\n<\/span>\n@<\/span>Controller<\/span><\/span>\npublic<\/span> <\/span>class<\/span> <\/span>MyController<\/span> {<\/span><\/span>\n    @<\/span>GetMapping<\/span>(<\/span>"<\/span>\/greeting<\/span>"<\/span>)<\/span><\/span>\n    <\/span>public<\/span> <\/span>String<\/span> <\/span>greeting<\/span>() {<\/span><\/span>\n        <\/span>return<\/span> <\/span>"<\/span>greeting<\/span>"<\/span>;  <\/span>\/\/ resolves to a view named "greeting"<\/span><\/span>\n    }<\/span><\/span>\n}<\/span><\/span>\n<\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
Add a page in the location src\/main\/resources\/templates\/greeting.html<\/code> with the same name as the string returned by the controller to return an HTML page from the server<\/p>\n\n\n\n
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<!<\/span>DOCTYPE<\/span> <\/span>htm<\/span>l<\/span>><\/span><\/span>\n<<\/span>html xmlns:th=<\/span>"<\/span><http:\/\/www.thymeleaf.org><\/span>"<\/span>><\/span><\/span>\n<<\/span>head<\/span>><\/span><\/span>\n    <\/span><<\/span>meta<\/span> <\/span>charset=<\/span>"<\/span>UTF-8<\/span>"<\/span> \/<\/span>><\/span><\/span>\n    <\/span><<\/span>title>Greeting<\/title><\/span><\/span>\n<<\/span>\/head<\/span>><\/span><\/span>\n<<\/span>body<\/span>><\/span><\/span>\n<<\/span>h<\/span>1><\/span>Hello<\/span>!<<\/span>\/h<\/span>1><\/span><\/span>\n<<\/span>\/body<\/span>><\/span><\/span>\n<<\/span>\/html<\/span>><\/span><\/span>\n<\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
Testing<\/h2>\n\n\n\n
Testing @Controller without REST<\/h3>\n\n\n\n
Using curl<\/code> to call our controller<\/p>\n\n\n\n
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curl<\/span> <\/span>-i<\/span> <\/span>http:\/\/localhost:8080\/greeting<\/span><\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
The result should look like this**:**<\/p>\n\n\n\n
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HTTP\/1.1<\/span> <\/span>200<\/span> <\/span><\/span>\nContent-Type:<\/span> <\/span>text\/html<\/span>;<\/span>charset<\/span>=<\/span>UTF-8<\/span><\/span>\nContent-Language:<\/span> <\/span>pt-BR<\/span><\/span>\nTransfer-Encoding:<\/span> <\/span>chunked<\/span><\/span>\n<\/span>\n<!<\/span>DOCTYPE<\/span> <\/span>htm<\/span>l<\/span>><\/span><\/span>\n<<\/span>html<\/span>><\/span><\/span>\n<<\/span>head<\/span>><\/span><\/span>\n    <\/span><<\/span>meta<\/span> <\/span>charset=<\/span>"<\/span>UTF-8<\/span>"<\/span> \/<\/span>><\/span><\/span>\n    <\/span><<\/span>title>Greeting<\/title><\/span><\/span>\n<<\/span>\/head<\/span>><\/span><\/span>\n<<\/span>body<\/span>><\/span><\/span>\n<<\/span>h<\/span>1><\/span>Hello<\/span>!<<\/span>\/h<\/span>1><\/span><\/span>\n<<\/span>\/body<\/span>><\/span><\/span>\n<<\/span>\/html<\/span>><\/span><\/span>\n<\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
Creating a REST endpoint with @ResponseBody<\/h3>\n\n\n\n
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import<\/span> org.springframework.http.ResponseEntity;<\/span><\/span>\nimport<\/span> org.springframework.stereotype.Controller;<\/span><\/span>\nimport<\/span> org.springframework.web.bind.annotation.GetMapping;<\/span><\/span>\nimport<\/span> org.springframework.web.bind.annotation.ResponseBody;<\/span><\/span>\n<\/span>\n@<\/span>Controller<\/span><\/span>\npublic<\/span> <\/span>class<\/span> <\/span>RestControllerExample<\/span> {<\/span><\/span>\n    @<\/span>GetMapping<\/span>(<\/span>"<\/span>\/api\/message<\/span>"<\/span>)<\/span><\/span>\n    @<\/span>ResponseBody<\/span><\/span>\n    <\/span>public<\/span> <\/span>ResponseEntity<\/span><String> <\/span>getMessage<\/span>() {<\/span><\/span>\n        <\/span>return<\/span> ResponseEntity.<\/span>ok<\/span>(<\/span>"<\/span>Hello, World!<\/span>"<\/span>);<\/span><\/span>\n    }<\/span><\/span>\n}<\/span><\/span>\n<\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
Testing @Controller with @ResponseBody<\/h3>\n\n\n\n
When calling with curl<\/code> :<\/p>\n\n\n\n
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<\/span>\ncurl<\/span> <\/span>-i<\/span> <\/span>http:\/\/localhost:8080\/api\/message<\/span><\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
It should return like this:<\/p>\n\n\n\n
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HTTP\/1.1<\/span> <\/span>200<\/span> <\/span><\/span>\nContent-Type:<\/span> <\/span>text\/plain<\/span>;<\/span>charset<\/span>=<\/span>UTF-8<\/span><\/span>\nContent-Length:<\/span> <\/span>13<\/span><\/span>\n<\/span>\nHello,<\/span> <\/span>World!<\/span><\/span>\n<\/span><\/code><\/pre><\/div>\n\n\n\n
Conclusion<\/h2>\n\n\n\n
This is one of the most important and common annotations when it comes to creating web applications with Spring. The usage is straightforward, making it easier to add new controllers and endpoints to your application.<\/p>\n\n\n\n
Willian Moya (@WillianFMoya) \/ X<\/a><\/p>\n\n\n\n
Willian Ferreira Moya | LinkedIn<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
What is? This class-level annotation tells Spring that your class is a controller. A controller is an entry point for a web application. This allows you to define a path to communicate with your backend using REST methods or by serving and responding html forms. This more general annotation allows your controller to serve REST […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[3,6],"tags":[13,18,22,23,24],"class_list":["post-300","post","type-post","status-publish","format-standard","hentry","category-java","category-spring","tag-java","tag-programming","tag-spring-boot","tag-spring-framework","tag-springboot"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts\/300","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=300"}],"version-history":[{"count":1,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts\/300\/revisions"}],"predecessor-version":[{"id":301,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=\/wp\/v2\/posts\/300\/revisions\/301"}],"wp:attachment":[{"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/springmasteryhub.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}