Feing client vs web client (#12968)

* implement code example for feignClient vs WebClient

* refactor code example for feignClient vs WebClient with /products endpoint

* fix PR comment

spring-reactive-modules/spring-5-reactive-3/pom.xml

@@ -20,6 +20,14 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-webflux</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-starter-openfeign</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.projectreactor</groupId>
             <artifactId>reactor-spring</artifactId>
@@ -35,10 +43,27 @@
             <artifactId>reactor-test</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
     </dependencies>
 
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-dependencies</artifactId>
+                <version>${spring-cloud.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
     <properties>
         <reactor-spring.version>1.0.1.RELEASE</reactor-spring.version>
+        <spring-cloud.version>2021.0.4</spring-cloud.version>
     </properties>
 
 </project>

spring-reactive-modules/spring-5-reactive-3/src/main/java/com/baeldung/webclient/Product.java

@@ -0,0 +1,13 @@
+package com.baeldung.webclient;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class Product {
+    private String title;
+    private String description;
+}

spring-reactive-modules/spring-5-reactive-3/src/main/java/com/baeldung/webclient/ProductsFeignClient.java

@@ -0,0 +1,15 @@
+package com.baeldung.webclient;
+
+import java.net.URI;
+import java.util.List;
+
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+
+@FeignClient(value = "productsBlocking", url = "http://localhost:8080")
+public interface ProductsFeignClient {
+
+    @RequestMapping(method = RequestMethod.GET, value = "/slow-service-products", produces = "application/json")
+    List<Product> getProductsBlocking(URI baseUrl);
+}

spring-reactive-modules/spring-5-reactive-3/src/main/java/com/baeldung/webclient/ProductsSlowServiceController.java

@@ -0,0 +1,21 @@
+package com.baeldung.webclient;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class ProductsSlowServiceController {
+
+    @GetMapping("/slow-service-products")
+    private List<Product> getAllProducts() throws  InterruptedException {
+        Thread.sleep(2000L); // delay
+        return Arrays.asList(
+          new Product("Fancy Smartphone", "A stylish phone you need"),
+          new Product("Cool Watch", "The only device you need"),
+          new Product("Smart TV", "Cristal clean images")
+        );
+    }
+}

spring-reactive-modules/spring-5-reactive-3/src/main/java/com/baeldung/webclient/WebClientApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.webclient;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.openfeign.EnableFeignClients;
+
+@SpringBootApplication
+@EnableFeignClients
+public class WebClientApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(WebClientApplication.class, args);
+    }
+}
+

spring-reactive-modules/spring-5-reactive-3/src/main/java/com/baeldung/webclient/WebController.java

@@ -0,0 +1,59 @@
+package com.baeldung.webclient;
+
+import java.net.URI;
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.reactive.function.client.WebClient;
+
+import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
+import reactor.core.publisher.Flux;
+
+@Slf4j
+@RestController
+public class WebController {
+
+    private static final int DEFAULT_PORT = 8080;
+
+    public static final String SLOW_SERVICE_PRODUCTS_ENDPOINT_NAME = "/slow-service-products";
+
+    @Setter
+    private int serverPort = DEFAULT_PORT;
+
+    @Autowired
+    private ProductsFeignClient productsFeignClient;
+
+    @GetMapping("/products-blocking")
+    public List<Product> getProductsBlocking() {
+        log.info("Starting BLOCKING Controller!");
+        final URI uri = URI.create(getSlowServiceBaseUri());
+
+        List<Product> result = productsFeignClient.getProductsBlocking(uri);
+        result.forEach(product -> log.info(product.toString()));
+        log.info("Exiting BLOCKING Controller!");
+        return result;
+    }
+
+    @GetMapping(value = "/products-non-blocking", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
+    public Flux<Product> getProductsNonBlocking() {
+        log.info("Starting NON-BLOCKING Controller!");
+        Flux<Product> productFlux = WebClient.create()
+          .get()
+          .uri(getSlowServiceBaseUri() + SLOW_SERVICE_PRODUCTS_ENDPOINT_NAME)
+          .retrieve()
+          .bodyToFlux(Product.class);
+
+        productFlux.subscribe(product -> log.info(product.toString()));
+        log.info("Exiting NON-BLOCKING Controller!");
+        return productFlux;
+    }
+
+    private String getSlowServiceBaseUri() {
+        return "http://localhost:" + serverPort;
+    }
+
+}

spring-reactive-modules/spring-5-reactive-3/src/test/java/com/baeldung/databuffer/DataBufferToInputStreamUnitTest.java

@@ -1,4 +1,4 @@
-package databuffer;
+package com.baeldung.databuffer;
 
 import com.baeldung.databuffer.DataBufferToInputStream;
 

spring-reactive-modules/spring-5-reactive-3/src/test/java/com/baeldung/webclient/WebControllerIntegrationTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.webclient;
+
+import static org.springframework.test.annotation.DirtiesContext.ClassMode.BEFORE_CLASS;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.test.web.server.LocalServerPort;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+@DirtiesContext(classMode = BEFORE_CLASS)
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT, classes = WebClientApplication.class)
+class WebControllerIntegrationTest {
+
+    @LocalServerPort
+    private int randomServerPort;
+
+    @Autowired
+    private WebTestClient testClient;
+
+    @Autowired
+    private WebController webController;
+
+    @BeforeEach
+    void setup() {
+        webController.setServerPort(randomServerPort);
+    }
+
+    @Test
+    void whenEndpointWithBlockingClientIsCalled_thenThreeProductsAreReceived() {
+        testClient.get()
+          .uri("/products-blocking")
+          .exchange()
+          .expectStatus().isOk()
+          .expectBodyList(Product.class).hasSize(3);
+    }
+
+    @Test
+    void whenEndpointWithNonBlockingClientIsCalled_thenThreeProductsAreReceived() {
+        testClient.get()
+          .uri("/products-non-blocking")
+          .exchange()
+          .expectStatus().isOk()
+          .expectBodyList(Product.class).hasSize(3);
+    }
+}