Swagger is an open source project used to generate the REST API documents for RESTful web services.

Add swagger and swagger-ui dependencies

<dependency>
   <groupId>io.springfox</groupId>
   <artifactId>springfox-swagger2</artifactId>
   <version>2.7.0</version>
</dependency>
<dependency>
   <groupId>io.springfox</groupId>
   <artifactId>springfox-swagger-ui</artifactId>
   <version>2.7.0</version>
</dependency>

Add Swagger Config class

@PropertySource("classpath:swagger.properties")
@Configuration
@EnableSwagger2
public class SwaggerConfig {
    private Logger log = LoggerFactory.getLogger(this.getClass());

    @Bean
    public Docket api() {
        log.info("setting up Docket..");
        Docket docket = new Docket(DocumentationType.SWAGGER_2)
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.folaukaveinga"))
                .paths(PathSelectors.any()).build().apiInfo(getApiInfo());
        
        log.info("docket setup!");
        
        return docket;
    }

    private ApiInfo getApiInfo() {
        Contact contact = new Contact("Folau Kaveinga", "folaukaveinga.org", "folaukaveinga@gmail.com");
        return new ApiInfoBuilder()
                .title("Spring Data Tutorial")
                .description("Spring Data API")
                .version("1.0.0")
                .contact(contact)
                .build();
    }

}

Anotate controller classes

1. Anotate Controller class with @Api
2. Anotate methods with @ApiOperation
3. Use @ApiParam to describe parameters

@Api(value = "users", produces = "Rest API for User operations", tags = "User Controller")
@RestController
@RequestMapping("/users")
public class UserController {

    private Logger      log = LoggerFactory.getLogger(this.getClass());

    @Autowired
    private UserService userService;

    @ApiOperation(value = "Get Member By Id")
    @GetMapping("/{id}")
    public ResponseEntity<User> getUserById(@ApiParam(name = "id", required = true, value = "id of member") @PathVariable("id") Long id) {
        log.info("get user by id: {}", id);

        return new ResponseEntity<>(userService.getById(id), HttpStatus.OK);
    }

}

Source code on Github