BAEL-4012 Add Netflix Feign (#10110)

* BAEL-4012 Add Netflix Feign

* BAEL-4012 Cleanup pom

spring-cloud/spring-cloud-netflix-feign/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.cloud</groupId>
+    <artifactId>spring-cloud-netlix-feign</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>spring-cloud-netflix-feign</name>
+    <description>Netflix Feign project for Spring Boot</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-boot-1</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-1</relativePath>
+    </parent>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-dependencies</artifactId>
+                <version>${spring-cloud.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-starter-feign</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>com.netflix.feign</groupId>
+            <artifactId>feign-okhttp</artifactId>
+            <version>${feign-ok.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpcore</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <spring-cloud.version>Camden.SR7</spring-cloud.version>
+        <feign-ok.version>8.18.0</feign-ok.version>
+        <!--
+        <spring-cloud.version>Hoxton.SR8</spring-cloud.version>
+        -->
+        <!--
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
+        -->
+    </properties>
+
+</project>

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/ExampleApplication.java

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+package com.baeldung.cloud.netflix.feign;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.netflix.feign.EnableFeignClients;
+
+@SpringBootApplication
+@EnableFeignClients
+public class ExampleApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ExampleApplication.class, args);
+    }
+
+}
+

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/client/JSONPlaceHolderClient.java

@@ -0,0 +1,25 @@
+package com.baeldung.cloud.netflix.feign.client;
+
+import com.baeldung.cloud.netflix.feign.config.ClientConfiguration;
+import com.baeldung.cloud.netflix.feign.hystrix.JSONPlaceHolderFallback;
+import com.baeldung.cloud.netflix.feign.model.Post;
+import org.springframework.cloud.netflix.feign.FeignClient;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+
+import java.util.List;
+
+@FeignClient(value = "jplaceholder",
+        url = "https://jsonplaceholder.typicode.com/",
+        configuration = ClientConfiguration.class,
+        fallback = JSONPlaceHolderFallback.class)
+public interface JSONPlaceHolderClient {
+
+    @RequestMapping(method = RequestMethod.GET, value = "/posts")
+    List<Post> getPosts();
+
+
+    @RequestMapping(method = RequestMethod.GET, value = "/posts/{postId}", produces = "application/json")
+    Post getPostById(@PathVariable("postId") Long postId);
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/config/ClientConfiguration.java

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+package com.baeldung.cloud.netflix.feign.config;
+
+import feign.Logger;
+import feign.RequestInterceptor;
+import feign.codec.ErrorDecoder;
+import feign.okhttp.OkHttpClient;
+
+import org.apache.http.entity.ContentType;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class ClientConfiguration {
+
+    @Bean
+    public Logger.Level feignLoggerLevel() {
+        return Logger.Level.FULL;
+    }
+
+    @Bean
+    public ErrorDecoder errorDecoder() {
+        return new ErrorDecoder.Default();
+    }
+
+    @Bean
+    public OkHttpClient client() {
+        return new OkHttpClient();
+    }
+
+    @Bean
+    public RequestInterceptor requestInterceptor() {
+        return requestTemplate -> {
+            requestTemplate.header("user", "ajeje");
+            requestTemplate.header("password", "brazof");
+            requestTemplate.header("Accept", ContentType.APPLICATION_JSON.getMimeType());
+        };
+    }
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/config/CustomErrorDecoder.java

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+package com.baeldung.cloud.netflix.feign.config;
+
+import com.baeldung.cloud.netflix.feign.exception.BadRequestException;
+import com.baeldung.cloud.netflix.feign.exception.NotFoundException;
+import feign.Response;
+import feign.codec.ErrorDecoder;
+
+public class CustomErrorDecoder implements ErrorDecoder {
+    @Override
+    public Exception decode(String methodKey, Response response) {
+
+        switch (response.status()){
+            case 400:
+                return new BadRequestException();
+            case 404:
+                return new NotFoundException();
+            default:
+                return new Exception("Generic error");
+        }
+    }
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/exception/BadRequestException.java

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+package com.baeldung.cloud.netflix.feign.exception;
+
+public class BadRequestException extends Exception {
+
+    public BadRequestException() {
+    }
+
+    public BadRequestException(String message) {
+        super(message);
+    }
+
+    public BadRequestException(Throwable cause) {
+        super(cause);
+    }
+
+    @Override
+    public String toString() {
+        return "BadRequestException: "+getMessage();
+    }
+
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/exception/NotFoundException.java

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+package com.baeldung.cloud.netflix.feign.exception;
+
+public class NotFoundException extends Exception {
+
+    public NotFoundException() {
+    }
+
+    public NotFoundException(String message) {
+        super(message);
+    }
+
+    public NotFoundException(Throwable cause) {
+        super(cause);
+    }
+
+    @Override
+    public String toString() {
+        return "NotFoundException: "+getMessage();
+    }
+
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/hystrix/JSONPlaceHolderFallback.java

@@ -0,0 +1,22 @@
+package com.baeldung.cloud.netflix.feign.hystrix;
+
+import com.baeldung.cloud.netflix.feign.client.JSONPlaceHolderClient;
+import com.baeldung.cloud.netflix.feign.model.Post;
+import org.springframework.stereotype.Component;
+
+import java.util.Collections;
+import java.util.List;
+
+@Component
+public class JSONPlaceHolderFallback implements JSONPlaceHolderClient {
+
+    @Override
+    public List<Post> getPosts() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public Post getPostById(Long postId) {
+        return null;
+    }
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/model/Post.java

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+package com.baeldung.cloud.netflix.feign.model;
+
+public class Post {
+
+    private String userId;
+    private Long id;
+    private String title;
+    private String body;
+
+    public String getUserId() {
+        return userId;
+    }
+
+    public void setUserId(String userId) {
+        this.userId = userId;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getBody() {
+        return body;
+    }
+
+    public void setBody(String body) {
+        this.body = body;
+    }
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/service/JSONPlaceHolderService.java

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+package com.baeldung.cloud.netflix.feign.service;
+
+import com.baeldung.cloud.netflix.feign.model.Post;
+
+import java.util.List;
+
+public interface JSONPlaceHolderService {
+
+    List<Post> getPosts();
+
+    Post getPostById(Long id);
+}

spring-cloud/spring-cloud-netflix-feign/src/main/java/com/baeldung/cloud/netflix/feign/service/impl/JSONPlaceHolderServiceImpl.java

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+package com.baeldung.cloud.netflix.feign.service.impl;
+
+import com.baeldung.cloud.netflix.feign.client.JSONPlaceHolderClient;
+import com.baeldung.cloud.netflix.feign.model.Post;
+import com.baeldung.cloud.netflix.feign.service.JSONPlaceHolderService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+public class JSONPlaceHolderServiceImpl implements JSONPlaceHolderService {
+
+    @Autowired
+    private JSONPlaceHolderClient jsonPlaceHolderClient;
+
+    @Override
+    public List<Post> getPosts() {
+        return jsonPlaceHolderClient.getPosts();
+    }
+
+    @Override
+    public Post getPostById(Long id) {
+        return jsonPlaceHolderClient.getPostById(id);
+    }
+}

spring-cloud/spring-cloud-netflix-feign/src/main/resources/application.properties

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+spring.application.name=netflix-feign
+logging.level.com.baeldung.cloud.netflix.feign.client=DEBUG
+feign.hystrix.enabled=true

spring-cloud/spring-cloud-netflix-feign/src/test/java/com/baeldung/cloud/netflix/feign/ExampleTestApplication.java

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+package com.baeldung.cloud.netflix.feign;
+
+import com.baeldung.cloud.netflix.feign.config.ClientConfiguration;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@EnableAutoConfiguration
+@ContextConfiguration(classes = { ClientConfiguration.class })
+public class ExampleTestApplication {
+    
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+}

spring-cloud/spring-cloud-netflix-feign/src/test/java/com/baeldung/cloud/netflix/feign/NetflixFeignUnitTest.java

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+package com.baeldung.cloud.netflix.feign;
+
+import com.baeldung.cloud.netflix.feign.model.Post;
+import com.baeldung.cloud.netflix.feign.service.JSONPlaceHolderService;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.util.List;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class NetflixFeignUnitTest {
+
+    @Autowired
+    private JSONPlaceHolderService jsonPlaceHolderService;
+
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+
+    @Test
+    public void whenGetPosts_thenListPostSizeGreaterThanZero() {
+
+        List<Post> posts = jsonPlaceHolderService.getPosts();
+
+        assertFalse(posts.isEmpty());
+    }
+
+    @Test
+    public void whenGetPostWithId_thenPostExist() {
+
+        Post post = jsonPlaceHolderService.getPostById(1L);
+
+        assertNotNull(post);
+    }
+
+}