Docker下的Spring Cloud三部曲之二：细说Spring Cloud开发

本文是《Docker下的Spring Cloud三部曲》系列的第二篇，详细讲解上一篇实例中用到的eureka、provider、consumer等三个应用的开发过程；

原文地址：http://blog.csdn.net/boling_cavalry/article/details/79134497

环境信息

回顾一下实战环境，如下图：

源码地址

上图的eureka、provider、consumer是三个spring boot的web工程，源码可以在GitHub下载，地址和链接信息如下表所示：

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项目中有多个工程，本次实战的工程是springcloudscaledemo，如下图红框所示：

如何将spring boot工程构建成docker镜像

如果您想了解如何将spring boot工程构建docker镜像，欢迎访问以下三篇实战文章：

1. 《maven构建docker镜像三部曲之一：准备环境》；

2. 《maven构建docker镜像三部曲之二：编码和构建镜像》;

3. 《maven构建docker镜像三部曲之三：推送到远程仓库(内网和阿里云)》;

本次实战用到的知识点主要集中在上面的第二部；

开发环境

本次实战开发环境的具体信息如下：

1. 操作系统：Ubuntu16；

2. Docker版本：17.03.2-ce；

3. JDK：1.8.0_151；

4. maven：3.3.3；

接下来我们依次开发eureka、provider、consumer等三个应用；

eureka-server应用的pom.xml

新建一个名为 eureka-server的spring boot应用，pom.xml内容如下：

<?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"> <modelVersion>4.0.0</modelVersion>

<groupId>com.bolingcavalry</groupId>
<artifactId>eureka-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>eureka-server</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Edgware.SR1</spring-cloud.version>
</properties>

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

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

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>

<!--新增的docker maven插件-->
<plugin>
<groupId>com.spotify</groupId>
<artifactId>docker-maven-plugin</artifactId>
<version>0.4.12</version>
<!--docker镜像相关的配置信息-->
<configuration>
<!--镜像名，这里用工程名-->
<imageName>bolingcavalry/${project.artifactId}</imageName>
<!--TAG,这里用工程版本号-->
<imageTags>
<imageTag>${project.version}</imageTag>
</imageTags>
<!--镜像的FROM，使用java官方镜像-->
<baseImage>java:8u111-jdk</baseImage>
<!--该镜像的容器启动后，直接运行spring boot工程-->
<entryPoint>["java", "-jar", "/${project.build.finalName}.jar"]</entryPoint>
<!--构建镜像的配置信息-->
<resources>
<resource>
<targetPath>/</targetPath>
<directory>${project.build.directory}</directory>
<include>${project.build.finalName}.jar</include>
</resource>
</resources>
</configuration>
</plugin>
</plugins>
</build>
</project>

pom.xml中的几个关键点如下：

1. spring cloud的版本是Edgware.SR1；

2. 添加spring-cloud-starter-eureka-server的依赖；

3. 添加spring-cloud-dependencies的依赖(pom的形式)；

4. 添加插件docker-maven-plugin，用于将当前工程制作成本地docker镜像；

eureka-server应用的源码

eureka-server应用只有一个java文件，内容如下：

package com.bolingcavalry.eurekaserver;

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

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

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

注意要添加@EnableEurekaServer注解；

eureka-server的配置信息

配置信息application.properties的内容如下：

server.port=8080

eureka.instance.hostname=localhost
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/

构建eureka-server应用的docker镜像

在pom.xml文件所在目录下，执行如下命令可以构建docker镜像：

mvn clean package -U -DskipTests docker:build

构建成功后，执行命令docker images可见新构建的镜像，如下：

ubuntu@VM-129-56-ubuntu:~$ sudo docker images
REPOSITORY                       TAG                 IMAGE ID            CREATED             SIZE
bolingcavalry/eureka-server      0.0.1-SNAPSHOT      80663220a5f5        35 hours ago        683 MB
bolingcavalry/eureka-server      latest              80663220a5f5        35 hours ago        683 MB

eureka-server的镜像OK后，我们接下来构建provide的镜像；

provider应用的pom.xml

新建一个名为service-provider的spring boot应用，pom.xml内容如下：

<?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"> <modelVersion>4.0.0</modelVersion>

<groupId>com.bolingcavalry</groupId>
<artifactId>service-provider</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>service-provider</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Edgware.SR1</spring-cloud.version>
</properties>

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

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>

<!--新增的docker maven插件-->
<plugin>
<groupId>com.spotify</groupId>
<artifactId>docker-maven-plugin</artifactId>
<version>0.4.12</version>
<!--docker镜像相关的配置信息-->
<configuration>
<!--镜像名，这里用工程名-->
<imageName>bolingcavalry/${project.artifactId}</imageName>
<!--TAG,这里用工程版本号-->
<imageTags>
<imageTag>${project.version}</imageTag>
</imageTags>
<!--镜像的FROM，使用java官方镜像-->
<baseImage>java:8u111-jdk</baseImage>
<!--该镜像的容器启动后，直接运行spring boot工程-->
<entryPoint>["java", "-jar", "/${project.build.finalName}.jar"]</entryPoint>
<!--构建镜像的配置信息-->
<resources>
<resource>
<targetPath>/</targetPath>
<directory>${project.build.directory}</directory>
<include>${project.build.finalName}.jar</include>
</resource>
</resources>
</configuration>
</plugin>
</plugins>
</build>
</project>

provider应用的源码

入口类ServiceProviderApplication的源码如下：

package com.bolingcavalry.serviceprovider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

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

注意要添加@EnableDiscoveryClient注解；

只有一个controller类UserController ，对外提供http服务：

@RestController
public class UserController {
@RequestMapping(value = "/getuserinfo/{id}", method = RequestMethod.GET)
public String getUserInfo(@PathVariable String id){
return String.format("user[%s]", id);
}

@RequestMapping(value = "/getuserinfo", method = RequestMethod.GET)
public String getUserInfoWithRequestParam(@RequestParam("id") String id, @RequestParam("name") String name){
return String.format("user [%s], id [%s], from server [%s]", name, id, getIPAddr());
}

/**
* 获取本机IP地址
* @return
*/
private static String getIPAddr(){
String hostAddress = null;
try{
InetAddress address = InetAddress.getLocalHost();
hostAddress = address.getHostAddress();
}catch (UnknownHostException e){
e.printStackTrace();
}

return hostAddress;
}
}

上面的controller提供两个http服务，getUserInfoWithRequestParam服务会返回应用所在机器的IP地址；

provider的配置信息

provider的配置信息存放在application.yml文件中，内容如下：

server:
port: 8080
spring:
application:
name: microservice-provider-user
eureka:
client:
serviceUrl:
defaultZone: http://eurekahost:8080/eureka/ instance:
prefer-ip-address: true

注意上面配置的注册中心地址为http://eurekahost:8080/eureka/，eurekahost在docker-compose中会作为link参数对应eureka server；

构建provider应用的docker镜像

在pom.xml文件所在目录下，执行如下命令可以构建docker镜像：

mvn clean package -U -DskipTests docker:build

构建成功后，执行命令docker images可见新构建的镜像，如下：

ubuntu@VM-129-56-ubuntu:~$ sudo docker images
REPOSITORY                       TAG                 IMAGE ID            CREATED             SIZE
bolingcavalry/eureka-server      0.0.1-SNAPSHOT      80663220a5f5        35 hours ago        683 MB
bolingcavalry/eureka-server      latest              80663220a5f5        35 hours ago        683 MB
bolingcavalry/service-provider   0.0.1-SNAPSHOT      a02f307bc1a9        22 hours ago        683 MB
bolingcavalry/service-provider   latest              a02f307bc1a9        22 hours ago        683 MB

provider已经OK，接下来是consumer工程；

consumer应用的pom.xml

新建一个名为service-consumer的spring boot应用，pom.xml内容如下：

<?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"> <modelVersion>4.0.0</modelVersion>

<groupId>com.bolingcavalry</groupId>
<artifactId>service-consumer</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>service-consumer</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Edgware.SR1</spring-cloud.version>
</properties>

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

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

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>

<!--新增的docker maven插件-->
<plugin>
<groupId>com.spotify</groupId>
<artifactId>docker-maven-plugin</artifactId>
<version>0.4.12</version>
<!--docker镜像相关的配置信息-->
<configuration>
<!--镜像名，这里用工程名-->
<imageName>bolingcavalry/${project.artifactId}</imageName>
<!--TAG,这里用工程版本号-->
<imageTags>
<imageTag>${project.version}</imageTag>
</imageTags>
<!--镜像的FROM，使用java官方镜像-->
<baseImage>java:8u111-jdk</baseImage>
<!--该镜像的容器启动后，直接运行spring boot工程-->
<entryPoint>["java", "-jar", "/${project.build.finalName}.jar"]</entryPoint>
<!--构建镜像的配置信息-->
<resources>
<resource>
<targetPath>/</targetPath>
<directory>${project.build.directory}</directory>
<include>${project.build.finalName}.jar</include>
</resource>
</resources>
</configuration>
</plugin>
</plugins>
</build>
</project>

和前面两个应用相比，这里要引入spring-cloud-starter-feign；

consumer的源码

入口类ServiceConsumerApplication 源码如下：

package com.bolingcavalry.serviceconsumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

@EnableDiscoveryClient
@SpringBootApplication
@EnableFeignClients
public class ServiceConsumerApplication {

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

注意要增加@EnableDiscoveryClient和@SpringBootApplication这两个注解；

增加一个带注解@FeignClient的接口，用于在spring cloud环境中声明远程调用信息：

@FeignClient(name = "microservice-provider-user")
public interface UserFeignClient {

@RequestMapping(value = "/getuserinfo", method = RequestMethod.GET)
String getUserInfoWithRequestParam(@RequestParam("id") String id, @RequestParam("name") String name);
}

增加一个controller类UserFacadeController，为浏览器访问提供http服务，并且在响应请求的时候会通过UserFeignClient接口的实现远程调用provider应用的服务：

@RestController
public class UserFacadeController {

@Autowired
private UserFeignClient userFeignClient;

@GetMapping("/user/{id}/{name}")
public String getUserInfo(@PathVariable("id") final String id, @PathVariable("name") final String name) {
return "1. ---" + userFeignClient.getUserInfoWithRequestParam(id, name);
}
}

consumer的配置信息

provider的配置信息存放在application.yml文件中，内容如下：

server:
port: 8080
spring:
application:
name: service-consumer
eureka:
client:
serviceUrl:
defaultZone: http://eurekahost:8080/eureka/ instance:
prefer-ip-address: true

注意上面配置的注册中心地址为http://eurekahost:8080/eureka/，eurekahost在docker-compose中会作为link参数对应eureka server；

构建provider应用的docker镜像

在pom.xml文件所在目录下，执行如下命令可以构建docker镜像：

mvn clean package -U -DskipTests docker:build

构建成功后，执行命令docker images可见新构建的镜像，如下：

ubuntu@VM-129-56-ubuntu:~$docker images
REPOSITORY                       TAG                 IMAGE ID            CREATED             SIZE
bolingcavalry/service-provider   0.0.1-SNAPSHOT      a02f307bc1a9        47 hours ago        683 MB
bolingcavalry/service-provider   latest              a02f307bc1a9        47 hours ago        683 MB
bolingcavalry/service-consumer   0.0.1-SNAPSHOT      ae6b37b99754        2 days ago          683 MB
bolingcavalry/service-consumer   latest              ae6b37b99754        2 days ago          683 MB
bolingcavalry/eureka-server      0.0.1-SNAPSHOT      80663220a5f5        2 days ago          683 MB
bolingcavalry/eureka-server      latest              80663220a5f5        2 days ago          683 MB

至此，本次实战所需的所有镜像都制作完毕，相关的demo工程的开发过程我们也一起过了一遍，上一章中的实战您已经可以独立做出来了，接下来的实战中，我们一起来尝试服务横向扩容；