94 lines
2.4 KiB
Plaintext
94 lines
2.4 KiB
Plaintext
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== Why is this an issue?
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Classes annotated as `@Controller` in Spring are responsible for handling incoming web requests.
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When annotating methods or the entire controller with `@ResponseBody`, the return value of said methods will be serialized and set as the response body.
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In other words, it tells the Spring framework that this method does not produce a view.
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This mechanism is commonly used to create API endpoints.
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Spring provides `@RestController` as a convenient annotation to replace the combination of `@Controller` and `@ResponseBody`.
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The two are functionally identical, so the single annotation approach is preferred.
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This rule will raise an issue on a class that is annotated with `@Controller` if:
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* the class is also annotated with `@ResponseBody` or
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* all methods in said class are annotated with `@ResponseBody`.
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== How to fix it
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Replace the `@Controller` annotation with the `@RestController` annotation and remove all `@ResponseBody` annotations from the class and its methods.
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=== Code examples
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==== Noncompliant code example
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[source,java,diff-id=1,diff-type=noncompliant]
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----
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@Controller
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@ResponseBody
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public class MyController {
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@GetMapping("/hello")
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public String hello() {
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return "Hello World!";
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}
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}
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----
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==== Compliant solution
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[source,java,diff-id=1,diff-type=compliant]
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----
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@RestController
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public class MyController {
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@GetMapping("/hello")
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public String hello() {
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return "Hello World!";
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}
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}
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----
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==== Noncompliant code example
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[source,java,diff-id=2,diff-type=noncompliant]
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----
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@Controller
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public class MyController {
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@ResponseBody
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@GetMapping("/hello")
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public String hello() {
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return "Hello World!";
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}
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@ResponseBody
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@GetMapping("/foo")
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public String foo() {
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return "Foo";
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}
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}
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----
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==== Compliant solution
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[source,java,diff-id=2,diff-type=compliant]
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----
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@RestController
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public class MyController {
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@GetMapping("/hello")
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public String hello() {
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return "Hello World!";
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}
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@GetMapping("/foo")
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public String foo() {
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return "Foo";
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}
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}
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----
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== Resources
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=== Articles & blog posts
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* Spring Guides - https://spring.io/guides/gs/rest-service/[Building a RESTful Web Service]
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* Baeldung - https://www.baeldung.com/spring-controller-vs-restcontroller[The Spring @Controller and @RestController Annotations]
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* Baeldung - https://www.baeldung.com/spring-request-response-body[Spring's RequestBody and ResponseBody Annotations]
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