首页手记 spring-cloud-square开发实战(三种类...

spring-cloud-square开发实战(三种类型全覆盖)

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Java Spring Cloud

欢迎访问我的GitHub

这里分类和汇总了欣宸的全部原创(含配套源码)：https://github.com/zq2599/blog_demos

本篇概览

前文《五分钟搞懂spring-cloud-square》详细介绍了什么是spring-cloud-square，以及三种实现类型的详细概念，爱动手的您已迫不及待想编码体验spring-cloud-square了，本篇咱们就来畅快实战，体验这个spring官方带给我们的smart client
如标题所述，接下里咱们会将spring-cloud-square提供的三种client都编码体验，总的来说本篇由以下内容构成：

新建maven工程，名为spring-cloud-square-tutorials，这是本篇所有应用的父工程，库版本在此工程中统一管理；
创建子工程eureka，作为注册中心
创建子工程client，放一些公用的数据结构
创建子工程provider，身份是服务提供者，接下来的三个用到spring-cloud-square的子工程，都调用provider的服务
创建子工程consumer-okhttp，基于spring-cloud-square的okhttp能力做远程调用
创建子工程consumer-retrofit-okhttp，基于spring-cloud-square的retrofit + okhttp能力做远程调用
创建子工程consumer-retrofit-webflux，基于spring-cloud-square的retrofit + webflux能力做远程调用

上述几个服务的关系如下图：

如何验证

代码写完之后，如何验证功能是否符合预期呢？本篇采用单元测试的方式，consumer-okhttp、consumer-retrofit-okhttp、consumer-retrofit-webflux这三个子工程都有自己的单元测试代码，执行通过就意味着代码功能符合预期了

源码下载

本篇实战中的完整源码可在GitHub下载到，地址和链接信息如下表所示(https://github.com/zq2599/blog_demos)：

名称	链接	备注
项目主页	https://github.com/zq2599/blog_demos	该项目在GitHub上的主页
git仓库地址(https)	https://github.com/zq2599/blog_demos.git	该项目源码的仓库地址，https协议
git仓库地址(ssh)	git@github.com:zq2599/blog_demos.git	该项目源码的仓库地址，ssh协议

这个git项目中有多个文件夹，本篇的源码在spring-cloud-square-tutorials文件夹下，如下图红框所示：

版本信息

本篇实战涉及到的主要版本情况如下：

JDK：1.8.0_291
IDEA：2021.1.3 (Ultimate Edition)
maven：3.8.1
操作系统：win10 64位
springboot：2.4.4
spring-cloud：2020.0.2
spring-cloud-square：0.4.0-SNAPSHOT

父工程spring-cloud-square-tutorials

父工程名为spring-cloud-square-tutorials，其pom.xml如下，除了依赖库的版本在此统一管理，还要注意的是两个仓库的引入（https://repo.spring.io/snapshot和https://repo.spring.io/milestone），引入它们是因为spring-cloud-square还在孵化阶段，没有发布到maven中央仓库：

<?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>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.bolingcavalry</groupId>
    <artifactId>spring-cloud-square-tutorials</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <java.version>1.8</java.version>
        <spring-cloud.version>2020.0.2</spring-cloud.version>
        <square.dependency.version>0.4.0-SNAPSHOT</square.dependency.version>
    </properties>

    <packaging>pom</packaging>
    <description>Demo project for Spring Cloud Square Retrofit Web</description>

    <modules>
        <module>provider</module>
        <module>eureka</module>
        <module>consumer-okhttp</module>
        <module>client</module>
        <module>consumer-retrofit-okhttp</module>
        <module>consumer-retrofit-webflux</module>
    </modules>

    <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>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <dependency>
                <groupId>com.squareup.okhttp3</groupId>
                <artifactId>okhttp</artifactId>
                <version>3.14.9</version>
                <scope>compile</scope>
            </dependency>

            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-classic</artifactId>
                <version>1.1.7</version>
            </dependency>

            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.16.16</version>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-square-okhttp</artifactId>
                <version>${square.dependency.version}</version>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-square-retrofit</artifactId>
                <version>${square.dependency.version}</version>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-boot-starter-webflux</artifactId>
                <version>${square.dependency.version}</version>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-square-retrofit-webclient</artifactId>
                <version>${square.dependency.version}</version>
            </dependency>

        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <!--skip deploy (this is just a test module) -->
                <artifactId>maven-deploy-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>
</project>

注册中心eureka

eureka应用并没有什么特别之处，pom.xml如下：

<?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">
    <parent>
        <artifactId>spring-cloud-square-tutorials</artifactId>
        <groupId>com.bolingcavalry</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>eureka</artifactId>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <start-class>com.bolingcavalry.eureka.EurekaApplication</start-class>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
<!--                <version>Finchley.BUILD-SNAPSHOT</version>-->
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>

            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <!-- defined in spring-cloud-starter-parent pom (as documentation hint),
                    but needs to be repeated here -->
                <configuration>
                    <requiresUnpack>
                        <dependency>
                            <groupId>com.netflix.eureka</groupId>
                            <artifactId>eureka-core</artifactId>
                        </dependency>
                        <dependency>
                            <groupId>com.netflix.eureka</groupId>
                            <artifactId>eureka-client</artifactId>
                        </dependency>
                    </requiresUnpack>
                </configuration>
            </plugin>

            <plugin>
                <!--skip deploy (this is just a test module) -->
                <artifactId>maven-deploy-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

中规中矩的配置文件application.yml，端口是8761，后面的应用也要保持一致：

server:
  port: 8761

spring:
  application:
    name: eureka

eureka:
  client:
    registerWithEureka: false
    fetchRegistry: false
  server:
    waitTimeInMsWhenSyncEmpty: 0

启动类EurekaApplication.java，记得用注解EnableEurekaServer开启eureka服务：

package com.bolingcavalry.eureka;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {
    public static void main(String[] args) throws Exception {
        SpringApplication.run(EurekaApplication.class, args);
    }
}

eureka应用已经完成，接下来是服务提供者了

服务提供者provider

-新建名为provider的应用，pom.xml如下，可见是个普通的web工程，会将自己注册到eureka上去：

<?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">
    <parent>
        <artifactId>spring-cloud-square-tutorials</artifactId>
        <groupId>com.bolingcavalry</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>provider</artifactId>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>com.bolingcavalry</groupId>
            <artifactId>client</artifactId>
            <version>${project.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-context</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <!-- 如果父工程不是springboot，就要用以下方式使用插件，才能生成正常的jar -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.bolingcavalry.provider.ProviderApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

配置文件application.yml：

spring:
  application:
    name: provider

server:
  port: 18080

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

启动类ProviderApplication .java：

package com.bolingcavalry.provider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

web服务类，可见对外提供了两个接口hello-str和hello-obj，前者返回字符串，或者返回对象：

package com.bolingcavalry.provider.controller;

import com.bolingcavalry.client.HelloResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Random;

@RestController
public class Hello {

    public static final String HELLO_PREFIX = "Hello World";

    @Autowired
    DiscoveryClient client;

    /**
     * 随机取一个provider实例，返回其描述信息，
     * 如果只有一个provider实例时，返回的就是当前服务信息
     * @return
     */
    private String providerDescription() {
        List<ServiceInstance> instances = client.getInstances("provider");
        ServiceInstance selectedInstance = instances
                .get(new Random().nextInt(instances.size()));

        return String.format("serviceId [%s], host [%s], port [%d]",
                selectedInstance.getServiceId(),
                selectedInstance.getHost(),
                selectedInstance.getPort());
    }

    private String dateStr(){
        return new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date());
    }

    @GetMapping("/hello-str")
    public String helloStr() {
        List<ServiceInstance> instances = client.getInstances("provider");
        ServiceInstance selectedInstance = instances
                .get(new Random().nextInt(instances.size()));
        return HELLO_PREFIX
                + " : "
                + providerDescription()
                + ", "
                + dateStr();
    }
    
    @GetMapping("/hello-obj")
    public HelloResponse helloObj(@RequestParam("name") String name) {
        return new HelloResponse(name, dateStr(), providerDescription());
    }
}

这个provider应用算是个最朴实无华的web服务了

启动服务

现在可以将eureka和provider服务先后启动，这样后面的应用编码完成后可以直接测试

consumer-okhttp，基于spring-cloud-square的okhttp能力

接下来要创建的应用consumer-okhttp，使用的是spring-cloud-square三种能力的第一种：okhttp
pom.xml内容如下，重点是spring-cloud-square-okhttp和spring-cloud-starter-loadbalancer这两个库的引入：

<?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">
    <parent>
        <artifactId>spring-cloud-square-tutorials</artifactId>
        <groupId>com.bolingcavalry</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>consumer-okhttp</artifactId>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>com.bolingcavalry</groupId>
            <artifactId>client</artifactId>
            <version>${project.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <scope>compile</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-square-okhttp</artifactId>
            <version>0.4.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-loadbalancer</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <!-- 如果父工程不是springboot，就要用以下方式使用插件，才能生成正常的jar -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.bolingcavalry.ConsumerApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

配置文件application.yml，还是常见的那几个配置：应用名、端口、eureka：

spring:
  application:
    name: consumer-okhttp

server:
  port: 18081

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

启动类：

package com.bolingcavalry.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

接下来是重要的配置类OkHttpClientConfig.java，用于实例化OkHttpClient.Builder对象并注册到spring环境：

package com.bolingcavalry.consumer;

import okhttp3.OkHttpClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
class OkHttpClientConfig{
    @Bean
    @LoadBalanced
    public OkHttpClient.Builder okHttpClientBuilder() {
        return new OkHttpClient.Builder();
    }
}

然后就可以使用这个Builder来创建OkHttpClient实例了，如下所示，可见入参request的url字段里使用了服务名provider，相当于OkHttpClient内如也能通过服务名取得具体的服务地址，至于是如何获取的，会在后面的文章详细分析，整段代码除了url使用服务名，并没有什么值得关注的地方了，普通的OkHttpClient使用而已：

package com.bolingcavalry.consumer.controller;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.io.IOException;

@RestController
public class RemoteHello {
    @Autowired
    private OkHttpClient.Builder builder;

    @GetMapping("/remote-str")
    public String hello() throws IOException {
        // 直接使用服务名
        Request request = new Request.Builder().url("http://provider/hello-str").build();

        // 远程访问
        Response response = builder.build().newCall(request).execute();

        return "get remote response : " + response.body().string();
    }
}

接下来看看单元测试代码，使用MockMvcRequestBuilders构造http请求，检查返回码和返回内容：

package com.bolingcavalry.consumer.controller;

import com.bolingcavalry.client.Constants;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import static org.hamcrest.Matchers.containsString;
import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@SpringBootTest
@AutoConfigureMockMvc
@Slf4j
class RemoteHelloTest {

    @Autowired
    private MockMvc mvc;

    @Test
    void hello() throws Exception {
        String responseString = mvc.perform(MockMvcRequestBuilders.get("/remote-str").accept(MediaType.APPLICATION_JSON))
                .andExpect(status().isOk())
                .andExpect(content().string(containsString(Constants.HELLO_PREFIX)))
                .andDo(print())
                .andReturn()
                .getResponse()
                .getContentAsString();

        log.info("response in junit test :\n" + responseString);
    }
}

如果eureka和provider都运行起来了，那么此时可以直接运行单元测试类，顺利通过测试，如下图：

consumer-retrofit-okhttp，基于spring-cloud-square的okhttp能力

接下来的两个应用都使用了当下热门的retrofit，再搭配Spring Cloud LoadBalance实现服务注册发现，当然了retrofit自身无法完成网络请求处理，要依赖其他库，先看okhttp库的
新建应用consumer-retrofit-okhttp，其pom.xml如下，要注意的必须依赖spring-cloud-square-retrofit和spring-cloud-square-okhttp，另外，为了：

<?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">
    <parent>
        <artifactId>spring-cloud-square-tutorials</artifactId>
        <groupId>com.bolingcavalry</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>consumer-retrofit-okhttp</artifactId>

    <dependencies>
        <dependency>
            <groupId>com.bolingcavalry</groupId>
            <artifactId>client</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</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-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-square-retrofit</artifactId>
            <version>0.4.0-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-square-okhttp</artifactId>
            <version>0.4.0-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <!--skip deploy (this is just a test module) -->
                <artifactId>maven-deploy-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

配置文件：

spring:
  application:
    name: consumer-retrofit-okhttp
server:
  port: 18082
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

启动类：

package com.bolingcavalry.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

配置类，和前一个应用的没啥区别，想想也是，底层可不都是okhttp么：

package com.bolingcavalry.consumer;

import okhttp3.OkHttpClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.square.retrofit.EnableRetrofitClients;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableRetrofitClients
class OkHttpClientConfig{
    @Bean
    @LoadBalanced
    public OkHttpClient.Builder okHttpClientBuilder() {
        return new OkHttpClient.Builder();
    }
}

接下来，有趣的部分出现了，先定义HelloService.java，里面的注解RetrofitClient指定了对应的服务名provider，在hello方法生，用GET注解指定了provider提供的web接口，而且hello方法的返回值Call，和provider服务中hello-obj的返回值HelloResponse也是对应的，还有就是hello的入参对应着provider服务中hello-obj的入参，很熟悉吧，确实，和feign太像了：

package com.bolingcavalry.consumer.service;

import com.bolingcavalry.client.HelloResponse;
import org.springframework.cloud.square.retrofit.core.RetrofitClient;
import retrofit2.Call;
import retrofit2.http.GET;
import retrofit2.http.Query;

@RetrofitClient("provider")
public interface HelloService {

    @GET("/hello-obj")
    Call<HelloResponse> hello(@Query("name") String name);
}

接下来是调用provider服务中hello-obj接口的代码RemoteHello.java，如下所示，神奇的一幕出现了，刚才咱们只写了HelloService接口，并没有写它的实现，但是通过Autowired注解却能从spring环境拿到实例直接使用，在hello方法中，并没有见到远程调用的代码，而是执行helloService.hello，就能发起远程调用，拿到provider返回的结果：

package com.bolingcavalry.consumer.controller;

import com.bolingcavalry.client.HelloResponse;
import com.bolingcavalry.consumer.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.io.IOException;

@RestController
public class RemoteHello {
    @Autowired(required = false)
    HelloService helloService;

    @GetMapping("/remote-obj")
    public HelloResponse hello(@RequestParam("name") String name) throws IOException {
        return helloService.hello(name).execute().body();
    }
}

看到这里，聪明的您一定会觉得欣宸就是个没见过世面的乡巴佬：定义HelloService 接口，无需开发实现类，这玩意在mybatis不就有了嘛，居然敢说"神奇"，我觉得您说得对，欣宸确实没见识，大惊小怪的…
单元测试类如下，由于返回的是json对象，因此可以用andExpect方法再配合MockMvcResultMatchers，对json进行检查：

package com.bolingcavalry.consumer.controller;

import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import static org.hamcrest.Matchers.is;
import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@SpringBootTest
@AutoConfigureMockMvc
@Slf4j
class RemoteHelloTest {

    private MockMvc mvc;

    @Autowired
    private WebApplicationContext webApplicationContext;

    @BeforeEach
    public void setUp() {
        // 在单元测试的时候，MockHttpServletResponse实例的characterEncoding默认是ISO-8859-1，
        // 得到的字符串打印出来也是乱码，
        // 下面的设置可以解决此问题
        if (null==mvc) {
            mvc = MockMvcBuilders
                    .webAppContextSetup(webApplicationContext)
                    .addFilter((request, response, chain) -> {
                        response.setCharacterEncoding("UTF-8"); // this is crucial
                        chain.doFilter(request, response);
                    }, "/*")
                    .build();
        }
    }

    @Test
    void hello() throws Exception {
        // 请求参数是用户名，实时生成一个
        String name = System.currentTimeMillis() + "程序员A";

        // 请求
        String responseString = mvc.perform(
                MockMvcRequestBuilders
                        .get("/remote-obj")
                        .param("name", name)
                        .accept(MediaType.APPLICATION_JSON)
        )
                .andExpect(status().isOk())                           // 验证状态
                .andExpect(jsonPath("$.name", is(name)))    // 验证json中返回的字段是否含有name
                .andDo(print())
                .andReturn()
                .getResponse()
                .getContentAsString();

        log.info("response in junit test :\n" + responseString);
    }
}

执行单元测试，如下图，顺利通过：

consumer-retrofit-webflux，基于spring-cloud-square的retrofit + webflux

最后登场的是consumer-retrofit-webflux，pom.xml如下，依赖库是spring-cloud-square-retrofit + spring-boot-starter-webflux的组合：

<?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">
    <parent>
        <artifactId>spring-cloud-square-tutorials</artifactId>
        <groupId>com.bolingcavalry</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>consumer-retrofit-webflux</artifactId>

    <dependencies>
        <dependency>
            <groupId>com.bolingcavalry</groupId>
            <artifactId>client</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</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-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-square-retrofit</artifactId>
            <version>0.4.0-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-square-retrofit-webclient</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <!--skip deploy (this is just a test module) -->
                <artifactId>maven-deploy-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

配置文件application.yml:

spring:
  application:
    name: consumer-retrofit-webflux

server:
  port: 18083

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

启动类RetrofitWebfluxApplication.java

package com.bolingcavalry.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

配置类AppConfiguration.java，使用的注解是EnableRetrofitClients，实例化的Buider对象是WebClient.Builder，和前面的不一样，要格外注意：

package com.bolingcavalry.consumer;

import okhttp3.OkHttpClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.square.retrofit.webclient.EnableRetrofitClients;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.reactive.function.client.WebClient;

@Configuration
@EnableRetrofitClients
class AppConfiguration {
    @Bean
    @LoadBalanced
    public WebClient.Builder builder() {
        return WebClient.builder();
    }
}

接下来是接口定义，注意hello方法的返回值是Mono，这是weflux风格的返回值，代表异步的0个或一个元素：

package com.bolingcavalry.consumer.service;

import com.bolingcavalry.client.HelloResponse;
import org.springframework.cloud.square.retrofit.core.RetrofitClient;
import reactor.core.publisher.Mono;
import retrofit2.http.GET;
import retrofit2.http.Query;

@RetrofitClient("provider")
public interface HelloService {

    @GET("/hello-obj")
    Mono<HelloResponse> hello(@Query("name") String name);
}

最后是单元测试类，和前面的没啥区别：

package com.bolingcavalry.consumer.controller;

import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;
import static org.hamcrest.Matchers.is;
import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@SpringBootTest
@AutoConfigureMockMvc
@Slf4j
class RemoteHelloTest {

    private MockMvc mvc;

    @Autowired
    private WebApplicationContext webApplicationContext;

    @BeforeEach
    public void setUp() {
        // 在单元测试的时候，MockHttpServletResponse实例的characterEncoding默认是ISO-8859-1，
        // 得到的字符串打印出来也是乱码，
        // 下面的设置可以解决此问题
        if (null==mvc) {
            mvc = MockMvcBuilders
                    .webAppContextSetup(webApplicationContext)
                    .addFilter((request, response, chain) -> {
                        response.setCharacterEncoding("UTF-8"); // this is crucial
                        chain.doFilter(request, response);
                    }, "/*")
                    .build();
        }
    }

    @Test
    void hello() throws Exception {
        // 请求参数是用户名，实时生成一个
        String name = System.currentTimeMillis() + "程序员B";

        // 请求
        String responseString = mvc.perform(
                MockMvcRequestBuilders
                        .get("/remote-obj")
                        .param("name", name)
                        .accept(MediaType.APPLICATION_JSON)
        )
                .andExpect(status().isOk())                           // 验证状态
                .andExpect(jsonPath("$.name", is(name)))    // 验证json中返回的字段是否含有name
                .andDo(print())
                .andReturn()
                .getResponse()
                .getContentAsString();

        log.info("response in junit test :\n" + responseString);
    }
}

运行单元测试，如下图，顺利通过，并且红框中所示的中文也没有乱码：

至此，spring-cloud-square的三种类型，咱们全部编码体验了一遍，聪明的您当然不会只满足于使用它们，接下来文章，咱们就去深入spring-cloud-square源码，研究其实现的细节，欣宸原创，必不会辜负您的期待！

我是欣宸，期待与您一同畅游Java世界…

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