Spring Boot
Spring Boot是一个应用框架，按照官网的介绍，可以轻松地创建独立运行的，生产级别的，基于Spring的应用，并且可以“直接运行”。坚持使用Spring框架与第三方库，使你可以轻松地开始使用。大多数Spring Boot应用只需要很少的Spring配置。
要获得更多关于Spring Boot的信息，请查阅http://projects.spring.io/spring-boot/
Flowable与Spring Boot的集成目前是我们与Spring的提交者共同开发的。
1.1. 兼容性 Compatibility
Spring Boot需要JDK 7运行时环境。可以通过调整配置，在JDK6下运行。请查阅Spring Boot的文档。
1.2. 开始 Getting started
Spring Boot提倡约定大于配置。要开始工作，简单地在你的项目中添加spring-boot-starters-basic依赖。例如在Maven中：
<dependency><groupId>org.flowable</groupId><artifactId>flowable-spring-boot-starter-basic</artifactId><version>${flowable.version}</version></dependency>就这么简单。这个依赖会自动向classpath添加正确的Flowable与Spring依赖。现在你可以编写Spring Boot应用了：
import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.Configuration;@Configuration@ComponentScan@EnableAutoConfigurationpublic class MyApplication { public static void main(String[] args) { SpringApplication.run(MyApplication.class, args); }}Flowable需要数据库存储数据。如果你运行上面的代码，会得到提示性的异常信息，指出需要在classpath中添加数据库驱动依赖。现在添加H2数据库依赖：
<dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><version>1.4.183</version></dependency>
应用这次可以启动了。你会看到类似这样的输出：
. ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v1.1.6.RELEASE) MyApplication : Starting MyApplication on ... s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@33cb5951: startup date [Wed Dec 17 15:24:34 CET 2014]; root of context hierarchy a.s.b.AbstractProcessEngineConfiguration : No process definitions were found using the specified path (classpath:/processes/**.bpmn20.xml). o.flowable.engine.impl.db.DbSqlSession : performing create on engine with resource org/flowable/db/create/flowable.h2.create.engine.sql o.flowable.engine.impl.db.DbSqlSession : performing create on history with resource org/flowable/db/create/flowable.h2.create.history.sql o.flowable.engine.impl.db.DbSqlSession : performing create on identity with resource org/flowable/db/create/flowable.h2.create.identity.sql o.a.engine.impl.ProcessEngineImpl : ProcessEngine default created o.a.e.i.a.DefaultAsyncJobExecutor : Starting up the default async job executor [org.flowable.spring.SpringAsyncExecutor]. o.a.e.i.a.AcquireTimerJobsRunnable : {} starting to acquire async jobs due o.a.e.i.a.AcquireAsyncJobsDueRunnable : {} starting to acquire async jobs due o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup MyApplication : Started MyApplication in 2.019 seconds (JVM running for 2.294)只是在classpath中添加依赖，并使用@EnableAutoConfiguration注解，就会在幕后发生很多事情：
自动创建了内存数据库（因为classpath中有H2驱动），并传递给Flowable流程引擎配置
创建并暴露了Flowable ProcessEngine bean
所有的Flowable服务都暴露为Spring bean
创建了Spring Job Executor
并且，processes目录下的任何BPMN 2.0流程定义都会被自动部署。创建processes目录，并在其中创建示例流程定义（命名为one-task-process.bpmn20.xml）:
<?xml version="1.0" encoding="UTF-8"?><definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:flowable="http://flowable.org/bpmn" targetNamespace="Examples"> <process id="oneTaskProcess" name="The One Task Process"> <startEvent id="theStart" /> <sequenceFlow id="flow1" sourceRef="theStart" targetRef="theTask" /> <userTask id="theTask" name="my task" /> <sequenceFlow id="flow2" sourceRef="theTask" targetRef="theEnd" /> <endEvent id="theEnd" /> </process></definitions>
然后添加下列代码，以测试部署是否生效。CommandLineRunner是一个特殊的Spring bean，在应用启动时执行：
@Configuration@ComponentScan@EnableAutoConfigurationpublic class MyApplication { public static void main(String[] args) { SpringApplication.run(MyApplication.class, args); } @Bean public CommandLineRunner init(final RepositoryService repositoryService, final RuntimeService runtimeService, final TaskService taskService) { return new CommandLineRunner() { @Override public void run(String... strings) throws Exception { System.out.println("Number of process definitions : " + repositoryService.createProcessDefinitionQuery().count()); System.out.println("Number of tasks : " + taskService.createTaskQuery().count()); runtimeService.startProcessInstanceByKey("oneTaskProcess"); System.out.println("Number of tasks after process start: " + taskService.createTaskQuery().count()); } }; }}会得到这样的输出：
Number of process definitions : 1 Number of tasks : 0 Number of tasks after process start : 1
