<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration">
<property name="dataSource" ref="dataSource"/>
<property name="databaseSchemaUpdate" value="drop-create" />
</bean>
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
<!-- 基本属性 url、user、password -->
<property name="url" value="jdbc:mysql://localhost:3306/activiti" />
<property name="username" value="root" />
<property name="password" value="123456" />
<!-- 配置初始化大小、最小、最大 -->
<property name="initialSize" value="5" />
<property name="minIdle" value="5" />
<property name="maxActive" value="10" />
<!-- 配置从连接池获取连接等待超时的时间 -->
<property name="maxWait" value="10000" />
<property name="timeBetweenEvictionRunsMillis" value="600000" />
<!-- 配置一个连接在池中最大空闲时间，单位是毫秒 -->
<property name="minEvictableIdleTimeMillis" value="300000" />
<!-- 设置从连接池获取连接时是否检查连接有效性，true时，每次都检查;false时，不检查 -->
<property name="testOnBorrow" value="false" />
<!-- 设置往连接池归还连接时是否检查连接有效性，true时，每次都检查;false时，不检查 -->
<property name="testOnReturn" value="false" />
<!-- 设置从连接池获取连接时是否检查连接有效性，true时，如果连接空闲时间超过minEvictableIdleTimeMillis进行检查，否则不检查;false时，不检查 -->
<property name="testWhileIdle" value="true" />
<!-- 检验连接是否有效的查询语句。如果数据库Driver支持ping()方法，则优先使用ping()方法进行检查，否则使用validationQuery查询进行检查。(Oracle jdbc Driver目前不支持ping方法) -->
<property name="validationQuery" value="SELECT 1" />
<!-- 打开PSCache，并且指定每个连接上PSCache的大小，Oracle等支持游标的数据库，打开此开关，会以数量级提升性能，具体查阅PSCache相关资料 -->
<property name="poolPreparedStatements" value="true" />
<property name="maxPoolPreparedStatementPerConnectionSize" value="20" />
<property name="filters" value="stat,slf4j" />
</bean>
</beans>
package help.lixin.activiti;
import org.activiti.engine.ProcessEngine;
import org.activiti.engine.ProcessEngines;
import org.activiti.engine.TaskService;
import org.junit.Test;
import static org.junit.Assert.*;
public class ProcessEngineTest {
@Test
public void getDefaultProcessEngine() {
// 1. 获得默认的流程引敬对象
ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine();
TaskService taskService = processEngine.getTaskService();
assertNotNull("task servier not null", taskService);
}
}
// field
public static final String NAME_DEFAULT = "default";
protected static boolean isInitialized;
public static ProcessEngine getDefaultProcessEngine() {
return getProcessEngine(NAME_DEFAULT);
}
public static ProcessEngine getProcessEngine(String processEngineName) {
// 判断是否初始化过
if (!isInitialized()) {
// 初始化
init();
}
return processEngines.get(processEngineName);
}
// field
protected static Map<String, ProcessEngine> processEngines = new HashMap<String, ProcessEngine>();
public synchronized static void init() {
// 再次判断是否否初始化过
if (!isInitialized()) {
if (processEngines == null) {
// 创建流程引擎载体
processEngines = new HashMap<String, ProcessEngine>();
}
// 获得ClassLoader
ClassLoader classLoader = ReflectUtil.getClassLoader();
Enumeration<URL> resources = null;
try {
// 尝试从ClassLoader中获得资源文件(activiti.cfg.xml)
resources = classLoader.getResources("activiti.cfg.xml");
} catch (IOException e) {
throw new ActivitiIllegalArgumentException("problem retrieving activiti.cfg.xml resources on the classpath: " + System.getProperty("java.class.path"), e);
}
// 把资源存入Set集合中,去除重复资源
Set<URL> configUrls = new HashSet<URL>();
while (resources.hasMoreElements()) {
configUrls.add(resources.nextElement());
}
// 遍历(activiti.cfg.xml)资源,挨个进行初始化
for (Iterator<URL> iterator = configUrls.iterator(); iterator.hasNext();) {
URL resource = iterator.next();
log.info("Initializing process engine using configuration '{}'", resource.toString());
// **********************初始化流程***************************
initProcessEngineFromResource(resource);
}
try {
resources = classLoader.getResources("activiti-context.xml");
} catch (IOException e) {
throw new ActivitiIllegalArgumentException("problem retrieving activiti-context.xml resources on the classpath: " + System.getProperty("java.class.path"), e);
}
while (resources.hasMoreElements()) {
URL resource = resources.nextElement();
log.info("Initializing process engine using Spring configuration '{}'", resource.toString());
initProcessEngineFromSpringResource(resource);
}
// 设置初始化完成
setInitialized(true);
} else {
log.info("Process engines already initialized");
}
}
// field
protected static Map<String, ProcessEngineInfo> processEngineInfosByName = new HashMap<String, ProcessEngineInfo>();
protected static Map<String, ProcessEngineInfo> processEngineInfosByResourceUrl = new HashMap<String, ProcessEngineInfo>();
protected static List<ProcessEngineInfo> processEngineInfos = new ArrayList<ProcessEngineInfo>();
private static ProcessEngineInfo initProcessEngineFromResource(URL resourceUrl) {
// 判断资源是否存在
ProcessEngineInfo processEngineInfo = processEngineInfosByResourceUrl.get(resourceUrl.toString());
// 如果资源存在的情况下
if (processEngineInfo != null) { // processEngineInfo=null
processEngineInfos.remove(processEngineInfo);
if (processEngineInfo.getException() == null) {
String processEngineName = processEngineInfo.getName();
processEngines.remove(processEngineName);
processEngineInfosByName.remove(processEngineName);
}
processEngineInfosByResourceUrl.remove(processEngineInfo.getResourceUrl());
}
// 获得资源的路径
// file:/Users/lixin/WorkspaceNetty/activiti-demo/target/classes/activiti.cfg.xml
String resourceUrlString = resourceUrl.toString();
try {
log.info("initializing process engine for resource {}", resourceUrl);
// 根据URL创建:ProcessEngine
ProcessEngine processEngine = buildProcessEngine(resourceUrl);
String processEngineName = processEngine.getName();
log.info("initialised process engine {}", processEngineName);
processEngineInfo = new ProcessEngineInfoImpl(processEngineName, resourceUrlString, null);
processEngines.put(processEngineName, processEngine);
processEngineInfosByName.put(processEngineName, processEngineInfo);
} catch (Throwable e) {
log.error("Exception while initializing process engine: {}", e.getMessage(), e);
processEngineInfo = new ProcessEngineInfoImpl(null, resourceUrlString, getExceptionString(e));
}
processEngineInfosByResourceUrl.put(resourceUrlString, processEngineInfo);
processEngineInfos.add(processEngineInfo);
return processEngineInfo;
}
// 根据URL构建:ProcessEngine
private static ProcessEngine buildProcessEngine(URL resource) {
InputStream inputStream = null;
try {
inputStream = resource.openStream();
// ************************创建:ProcessEngineConfiguration******************************
ProcessEngineConfiguration processEngineConfiguration = ProcessEngineConfiguration.createProcessEngineConfigurationFromInputStream(inputStream);
// ************************调用:ProcessEngineConfiguration.buildProcessEngine()******************************
return processEngineConfiguration.buildProcessEngine();
} catch (IOException e) {
throw new ActivitiIllegalArgumentException("couldn't open resource stream: " + e.getMessage(), e);
} finally {
IoUtil.closeSilently(inputStream);
}
}
public static ProcessEngineConfiguration createProcessEngineConfigurationFromInputStream(InputStream inputStream) {
return createProcessEngineConfigurationFromInputStream(inputStream, "processEngineConfiguration");
}
public static ProcessEngineConfiguration createProcessEngineConfigurationFromInputStream(InputStream inputStream, String beanName) {
// ******************************************************
return BeansConfigurationHelper.parseProcessEngineConfigurationFromInputStream(inputStream, beanName);
}
public static ProcessEngineConfiguration parseProcessEngineConfigurationFromResource(String resource, String beanName) {
Resource springResource = new ClassPathResource(resource);
return parseProcessEngineConfiguration(springResource, beanName);
}
public static ProcessEngineConfiguration parseProcessEngineConfiguration(Resource springResource, String beanName) {
// 创建Spring 框架中 DefaultListableBeanFactory
DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
// 创建XmlBeanDefinitionReader,解析XML中的Bean后将Bean信息存入:DefaultListableBeanFactory中
XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);
xmlBeanDefinitionReader.setValidationMode(XmlBeanDefinitionReader.VALIDATION_XSD);
// 解析资源
xmlBeanDefinitionReader.loadBeanDefinitions(springResource);
// 从Spring容器中获得流程引擎对象(beanName = processEngineConfiguration)
// Spring 实例化:StandaloneProcessEngineConfiguration时
// 同时会实例化父类(ProcessEngineConfigurationImpl)的各个成员属性
// repositoryService
// runtimeService
// historyService
// identityService
// taskService
// formService
// managementService
// dynamicBpmnService
// **************************将Bean初始化交给Spring**********************************
ProcessEngineConfigurationImpl processEngineConfiguration = (ProcessEngineConfigurationImpl) beanFactory.getBean(beanName);
// 将Spring BeanFactory通过:SpringBeanFactoryProxyMap进行包裹
// 并设置回: processEngineConfiguration 中
processEngineConfiguration.setBeans(new SpringBeanFactoryProxyMap(beanFactory));
return processEngineConfiguration;
}
Object
ProcessEngineConfiguration
ProcessEngineConfigurationImpl
StandaloneProcessEngineConfiguration
public class StandaloneProcessEngineConfiguration
// 继承:ProcessEngineConfigurationImpl
extends ProcessEngineConfigurationImpl {
@Override
public CommandInterceptor createTransactionInterceptor() {
return null;
}// end createTransactionInterceptor
}
public abstract class ProcessEngineConfigurationImpl
// 继承:ProcessEngineConfiguration
extends ProcessEngineConfiguration {
// SERVICES /////////////////////////////////////////////////////////////////
protected RepositoryService repositoryService = new RepositoryServiceImpl();
protected RuntimeService runtimeService = new RuntimeServiceImpl();
protected HistoryService historyService = new HistoryServiceImpl(this);
protected IdentityService identityService = new IdentityServiceImpl();
protected TaskService taskService = new TaskServiceImpl(this);
protected FormService formService = new FormServiceImpl();
protected ManagementService managementService = new ManagementServiceImpl();
protected DynamicBpmnService dynamicBpmnService = new DynamicBpmnServiceImpl(this);
private static ProcessEngine buildProcessEngine(URL resource) {
InputStream inputStream = null;
try {
inputStream = resource.openStream();
ProcessEngineConfiguration processEngineConfiguration = ProcessEngineConfiguration.createProcessEngineConfigurationFromInputStream(inputStream);
// buildProcessEngine
return processEngineConfiguration.buildProcessEngine();
} catch (IOException e) {
throw new ActivitiIllegalArgumentException("couldn't open resource stream: " + e.getMessage(), e);
} finally {
IoUtil.closeSilently(inputStream);
}
}
public ProcessEngine buildProcessEngine() {
// 调用 init
init();
// 创建流程引擎对象(并传入当前对象)
ProcessEngineImpl processEngine = new ProcessEngineImpl(this);
if (isActiviti5CompatibilityEnabled && activiti5CompatibilityHandler != null) {
Context.setProcessEngineConfiguration(processEngine.getProcessEngineConfiguration());
activiti5CompatibilityHandler.getRawProcessEngine();
}
// 调用后置处理
postProcessEngineInitialisation();
return processEngine;
} //end buildProcessEngine
