不熟悉Docker的朋友可以先看看：Docker快速搭建PHP+Nginx+Mysql环境，本文也在此基础上继续讲解

今天我们讲Docker构建 -> 运行 -> 发布Springboot项目

编写Springboot项目

编写一个简单的hello world项目

HelloWorld

新建一个springboot项目，直接在aplication中添加一个可访问的地址

@SpringBootApplication
@RestController
public class Application {

    @RequestMapping("/")
    public String home() {
        return "Hello Docker World.";
    }

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

}

Gradle

接下来配置gradle

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath('org.springframework.boot:spring-boot-gradle-plugin:1.3.3.RELEASE')
// tag::build[]
        classpath('se.transmode.gradle:gradle-docker:1.2')
// end::build[]
    }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'
// tag::plugin[]
apply plugin: 'docker'
// end::plugin[]

// This is used as the docker image prefix (org)
group = 'gregturn'

jar {
    baseName = 'docker-spring-boot-gradle'
    version =  '1.0.0'
}

// tag::task[]
task buildDocker(type: Docker, dependsOn: build) {
  push = true
  applicationName = jar.baseName
  dockerfile = file('src/main/docker/Dockerfile')
  doFirst {
    copy {
      from jar
      into stageDir
    }
  }
}
// end::task[]

repositories {
    mavenCentral()
}

sourceCompatibility = 1.8
targetCompatibility = 1.8

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web") 
    testCompile("org.springframework.boot:spring-boot-starter-test")
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.3'
}

Dockerfile

Docker 使用 Dockerfile 文件格式来指定 image 层

创建文件 src/main/docker/Dockerfile:

FROM frolvlad/alpine-oraclejdk8:slim
VOLUME /tmp
ADD docker-spring-boot-gradle-1.0.0.jar app.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

解释下这个配置文件：

VOLUME 指定了临时文件目录为/tmp。其效果是在主机 /var/lib/docker 目录下创建了一个临时文件，并链接到容器的/tmp。改步骤是可选的，如果涉及到文件系统的应用就很有必要了。/tmp目录用来持久化到 Docker 数据文件夹，因为 Spring Boot 使用的内嵌 Tomcat 容器默认使用/tmp作为工作目录
项目的 jar 文件作为 “app.jar” 添加到容器的
ENTRYPOINT 执行项目 app.jar。为了缩短 Tomcat 启动时间，添加一个系统属性指向 “/dev/urandom” 作为 Entropy Source

项目容器化

上面的springboot项目完成后push到github中，然后将项目clone到要部署的主机上，我这里clone到/data/source文件夹中，进入到项目文件夹中/data/source/xxx

构建 Docker Image

执行构建成为 docker image:

gradle build buildDocker

运行 Docker Image

docker run -p 8080:8080 -t waylau/docker-spring-boot-gradle

[root@waylau spring-boot]# docker run -p 8080:8080 -t waylau/docker-spring-boot-gradle

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.3.3.RELEASE)

2016-03-20 08:45:51.276  INFO 1 --- [           main] c.waylau.docker_spring_boot.Application  : Starting Application v1.0.0 on 048fb623038f with PID 1 (/app.jar started by root in /)
2016-03-20 08:45:51.289  INFO 1 --- [           main] c.waylau.docker_spring_boot.Application  : No active profile set, falling back to default profiles: default
2016-03-20 08:45:51.722  INFO 1 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@669af5fc: startup date [Sun Mar 20 08:45:51 GMT 2016]; root of context hierarchy
2016-03-20 08:45:54.874  INFO 1 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'beanNameViewResolver' with a different definition: replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]]
2016-03-20 08:45:57.893  INFO 1 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2016-03-20 08:45:57.982  INFO 1 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-03-20 08:45:57.984  INFO 1 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.0.32
2016-03-20 08:45:58.473  INFO 1 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2016-03-20 08:45:58.473  INFO 1 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 6877 ms
2016-03-20 08:45:59.672  INFO 1 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2016-03-20 08:45:59.695  INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-03-20 08:45:59.701  INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-03-20 08:45:59.703  INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-03-20 08:45:59.703  INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]
2016-03-20 08:46:00.862  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@669af5fc: startup date [Sun Mar 20 08:45:51 GMT 2016]; root of context hierarchy
2016-03-20 08:46:01.166  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto public java.lang.String com.waylau.docker_spring_boot.Application.home()
2016-03-20 08:46:01.189  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2016-03-20 08:46:01.190  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2016-03-20 08:46:01.302  INFO 1 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-03-20 08:46:01.302  INFO 1 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-03-20 08:46:01.438  INFO 1 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-03-20 08:46:01.833  INFO 1 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-03-20 08:46:02.332  INFO 1 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2016-03-20 08:46:02.343  INFO 1 --- [           main] c.waylau.docker_spring_boot.Application  : Started Application in 13.194 seconds (JVM running for 15.828)

访问项目

如果程序正确运行，浏览器访问 http://localhost:8080/，可以看到页面 “Hello Docker World.” 字样。

推送镜像到docker hub

首先，你在 Docker Hub 要有注册账号，且创建了相应的库；

其次，docker 推送前，先要登录，否则报unauthorized: access to the requested resource is not authorized的错误

登录

docker login

输出为：

[root@waylau spring-boot]# docker login
Username: waylau
Password: 
Email: waylau521@gmail.com
WARNING: login credentials saved in /root/.docker/config.json
Login Succeeded

执行推送

docker push waylau/docker-spring-boot-gradle

[root@waylau spring-boot]# docker push waylau/docker-spring-boot-gradle
The push refers to a repository [docker.io/waylau/docker-spring-boot-gradle]
751d29eef02e: Layer already exists 
4da3741f39c7: Pushed 
5f70bf18a086: Layer already exists 
7e4d0cb13643: Layer already exists 
8f045733649f: Layer already exists 
latest: digest: sha256:eb4d5308ba1bb27489d808279e74784bda6761b3574f4298d746abba59b35164 size: 9415

镜像加速器

Docker Hub 在国外，有时候拉取 Image 极其缓慢，可以使用国内的镜像来实现加速

阿里云

echo "DOCKER_OPTS=\"--registry-mirror=https://yourlocation.mirror.aliyuncs.com\"" | sudo tee -a /etc/default/docker
sudo service docker restart

其中 https://yourlocation.mirror.aliyuncs.com 是您在阿里云注册后的专属加速器地址：

DaoCloud

sudo echo “DOCKER_OPTS=\”\$DOCKER_OPTS –registry-mirror=http://your-id.m.daocloud.io -d\”” >> /etc/default/docker
sudo service docker restart

其中 http://your-id.m.daocloud.io 是您在 DaoCloud 注册后的专属加速器地址：

配置Nginx

在/data/nginx/文件夹中创建一个conf文件，编写配置文件

server {
    listen       80;
    server_name  springboot.notemi.cn;

    #charset koi8-r;
    access_log  /var/log/nginx/springboot_nginx.log  combined;

    location / {
        proxy_pass http://172.18.6.31:9001;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Port $server_port;
    }
}

172.18.6.31:9001 是项目的内网地址及端口，再将域名解析到服务器后，我们就能通过springboot.notemi.cn访问项目了。

源码

获取项目源码， https://github.com/waylau/docker-demos 中的 samples/spring-boot-gradle

获取项目镜像， 执行

docker pull waylau/docker-spring-boot-gradle

参考资料

• http://spring.io/guides/gs/spring-boot-docker/
• https://hub.docker.com/r/waylau/docker-spring-boot-gradle/
• https://waylau.com/docker-spring-boot-gradle/