Spring REST Qualifier HTTP Server Tutorial – Spring REST Qualifier Tutorial

Spring REST Qualifier Tutorial

This tutorial demonstrates @Qualifier injection in OfficeFloor REST service methods. When the Spring application context contains multiple beans of the same type, annotating a service method parameter with @Qualifier("name") selects the specific bean to inject.

The tutorial defines two Greeter implementations — one formal, one casual — and exposes each at its own endpoint.

Tutorial Source

Maven dependency

		<dependency>
			<groupId>net.officefloor.springboot</groupId>
			<artifactId>officefloor-rest-spring-boot-starter</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

Application class

@SpringBootApplication
public class SpringRestQualifierApplication {

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

The `Greeter` interface

public interface Greeter {

	String greet(String name);
}

Two beans of the same type

Each implementation is annotated with both @Component and @Qualifier, giving it a distinct qualifier name that OfficeFloor can match against service method parameters:

@Component
@Qualifier("formal")
public class FormalGreeter implements Greeter {

	@Override
	public String greet(String name) {
		return "Good day, " + name + ".";
	}
}

@Component
@Qualifier("casual")
public class CasualGreeter implements Greeter {

	@Override
	public String greet(String name) {
		return "Hey " + name + "!";
	}
}

Service methods — selecting by qualifier

@Qualifier("formal") on the parameter tells OfficeFloor to inject the formal bean. @Qualifier("casual") selects the casual bean. The name query parameter defaults to World when not supplied:

public class FormalGreetingService {

	public void service(
			@RequestParam(name = "name", required = false, defaultValue = "World") String name,
			@Qualifier("formal") Greeter greeter,
			ObjectResponse<String> response) {
		response.send(greeter.greet(name));
	}
}

public class CasualGreetingService {

	public void service(
			@RequestParam(name = "name", required = false, defaultValue = "World") String name,
			@Qualifier("casual") Greeter greeter,
			ObjectResponse<String> response) {
		response.send(greeter.greet(name));
	}
}

YAML endpoint files

service:
  class: net.officefloor.tutorial.springrestqualifier.FormalGreetingService

service:
  class: net.officefloor.tutorial.springrestqualifier.CasualGreetingService

Testing

@SpringBootTest
@AutoConfigureMockMvc
public class SpringRestQualifierTest {

	@Autowired
	private MockMvc mvc;

	@Test
	public void formalGreeting() throws Exception {
		mvc.perform(get("/greet/formal?name=Daniel").accept(MediaType.APPLICATION_JSON))
				.andExpect(status().isOk())
				.andExpect(content().string(equalTo("Good day, Daniel.")));
	}

	@Test
	public void casualGreeting() throws Exception {
		mvc.perform(get("/greet/casual?name=Daniel").accept(MediaType.APPLICATION_JSON))
				.andExpect(status().isOk())
				.andExpect(content().string(equalTo("Hey Daniel!")));
	}
}

The Spring REST Data JPA tutorial demonstrates Spring Data JPA integration with OfficeFloor transaction governance.