使用自定义注释在方法级别为控制器中的 GET、PUT、POST、DELETE 映射添加前缀或后缀 - Spring REST 控制器

Question

I am trying to add a prefix or suffix in the controller at the method level on top of GET, POST, PUT, DELETE mappings.

Controller class

@RestController
@RequestMapping("/something")
public class SomeController {
@PutMapping("/some/path/")
public ResponseEntity<ApiResponse<String>> someMethod() {
....
}
...
}

So, basically, the above request URL should be something like : http://localhost:8080/something/some/path/

Now, I just want to add some prefix or suffix whatever is feasible to the request URL which will be something like : http://localhost:8080/something/read/some/path/ or http://localhost:8080/something/some/path/read/ the extra "/read" which needs to be added to the request URL as a prefix or suffix. I can do this directly by adding this to the PutMapping value, but I want to decorate it somewhat using annotation like @Read

So, the updated Controller class will be like

@RestController
@RequestMapping("/something")
public class SomeController {
@Read
@PutMapping("/some/path/")
public ResponseEntity<ApiResponse<String>> someMethod() {
....
}
...
}

and the same way updated request URL will be like : http://localhost:8080/something/read/some/path/

I am unable to find a better way to do this. Till now I have only achieved adding a class-level prefix using custom annotation.

Can anyone please help with the above requirement.? Thank you !!

I am also curious to know whether is achievable or not even?

Answer 1

Using such way of path extension make your code less understandable. (maybe you should read more about RESTful API) But spring can do almost everything you want.

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.web.servlet.WebMvcRegistrations;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;
import java.util.stream.Stream;

@SpringBootApplication
public class DemoApplication {

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.METHOD)
    public @interface Read {
    }

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.METHOD)
    public @interface Write {
    }

    @Bean
    public WebMvcRegistrations webMvcRegistrations() {
        return new WebMvcRegistrations() {
            @Override
            public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {
                return new RequestMappingHandlerMapping() {
                    @Override
                    protected RequestMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
                        RequestMappingInfo defaultRequestMappingInfo = super.getMappingForMethod(method, handlerType);
                        if (defaultRequestMappingInfo == null) {
                            return null;
                        }
                        String pathSuffix;
                        if (method.isAnnotationPresent(Read.class)) {
                            pathSuffix = "read";
                        } else if (method.isAnnotationPresent(Write.class)) {
                            pathSuffix = "write";
                        } else {
                            return defaultRequestMappingInfo;
                        }
                        //extend path by mutating configured request mapping info
                        RequestMappingInfo.Builder mutateBuilder = defaultRequestMappingInfo.mutate();
                        mutateBuilder.paths(
                                defaultRequestMappingInfo.getPatternValues().stream()
                                        .map(path -> path + "/" + pathSuffix)
                                        .toArray(String[]::new)
                        );
                        return mutateBuilder.build();
                    }
                };
            }
        };
    }

    @RestController
    @RequestMapping("/books")
    public static class BooksController {

        @Read
        @GetMapping("/{id}")
        public String readBook(@PathVariable("id") String bookId) {
            return bookId;
        }
    }

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

Extension point is here, you can change path like you want.

Example:

request: http://localhost:8080/books/asd

response: 404

output:

2022-06-27 10:49:48.671 DEBUG 8300 --- [nio-8080-exec-2] com.example.demo.DemoApplication$1$1     : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#errorHtml(HttpServletRequest, HttpServletResponse)

request: http://localhost:8080/books/asd/read

response: asd

output:

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.7.0)

2022-06-27 10:48:53.622  INFO 8300 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication using Java 1.8.0_312 on DESKTOP with PID 8300 ()
2022-06-27 10:48:53.624 DEBUG 8300 --- [           main] com.example.demo.DemoApplication         : Running with Spring Boot v2.7.0, Spring v5.3.20
2022-06-27 10:48:53.625  INFO 8300 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to 1 default profile: "default"
2022-06-27 10:48:54.227  INFO 8300 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2022-06-27 10:48:54.233  INFO 8300 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2022-06-27 10:48:54.233  INFO 8300 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.63]
2022-06-27 10:48:54.298  INFO 8300 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2022-06-27 10:48:54.298  INFO 8300 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 643 ms
2022-06-27 10:48:54.473 DEBUG 8300 --- [           main] com.example.demo.DemoApplication$1$1     : 3 mappings in 'requestMappingHandlerMapping'
2022-06-27 10:48:54.536  INFO 8300 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2022-06-27 10:48:54.543  INFO 8300 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 1.199 seconds (JVM running for 1.827)
2022-06-27 10:49:01.196  INFO 8300 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2022-06-27 10:49:01.196  INFO 8300 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2022-06-27 10:49:01.197  INFO 8300 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms
2022-06-27 10:49:01.210 DEBUG 8300 --- [nio-8080-exec-1] com.example.demo.DemoApplication$1$1     : Mapped to com.example.demo.DemoApplication$BooksController#readBook(String)

dependencies

org.springframework.boot:spring-boot-starter-web

application.properties

logging.level.com.example.demo=debug