工作流activiti-02事物控制、流程引擎创建详解编程语言

使用activiti中有个很重要的问题就是需要保证事物的控制

activiti使用的是mybatis作为orm技术封装了一系列的操作数据库操作这也就是大家调用的api 操作的数据库表都是activit自带的数据表一般情况下使用spring整合

activiti的事物是很强大的但是往往就不能如愿因为公司使用的都是自己的框架不能利用spring来整合事物。

通过java程序来控制activiti的事物

activiti的事物依赖于TransactionFactory 在创建流程引擎ProcessEngine来指定事物工厂，其原因分析如下：

创建流程引擎： ProcessEngine processEngine = conf.buildProcessEngine() ;

conf为StandaloneProcessEngineConfiguration的对象其buildProcessEngine方法如下：

 public ProcessEngine buildProcessEngine() { 
    init(); 
    return new ProcessEngineImpl(this); 
  } 

//调用init方法  
 
  protected void init() {
    initHistoryLevel();
    initExpressionManager();
    initVariableTypes();
    initBeans();
    initFormEngines();
    initFormTypes();
    initScriptingEngines();
    initBusinessCalendarManager();
    initCommandContextFactory();
    initTransactionContextFactory();
    initCommandExecutors();
    initServices();
    initIdGenerator();
    initDeployers();
    initJobExecutor();
    initMailScanner();
    initDataSource();
    initTransactionFactory();
    initSqlSessionFactory();
    initSessionFactories();
    initJpa();
    initDelegateInterceptor();
    initEventHandlers();
  }
其中初始化了很多信息，可以依次看看源码  其中initTransactionFactory（）方法代码如下： 

  // myBatis SqlSessionFactory ////////////////////////////////////////////////
  
  protected void initTransactionFactory() {
    if (transactionFactory==null) {
      if (transactionsExternallyManaged) {
        transactionFactory = new ManagedTransactionFactory();
      } else {
        transactionFactory = new JdbcTransactionFactory();
      }
    }
  }

其中transactionFactory为 protected TransactionFactory transactionFactory; 类中的属性
由代码可知如果transactionFactory不为空则事物工厂为JdbcTransactionFactory的实例化对象
那么设置StandaloneProcessEngineConfiguration的transactionFactory的值为一JdbcTransactionFactory对象即可

代码如下：创建一个servlet监听器在容器启动的时候创建一个流程引擎（需要配置web.xml文件）

/********************************************************************** 
 *  
 * FILE : MyServletListener.java 
 * CLASS : MyServletListener 
 * 
 * AUTHOR : Liaokailin 
 * 
 * FUNCTION :  
 * 
 * 
 * Contact: Sina L凯林
 * 
 *====================================================================== 
 * CHANGE HISTORY LOG 
 *---------------------------------------------------------------------- 
 * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ. 
 *---------------------------------------------------------------------- 
 * 		    |2014年1月17日|Liaokailin| Created | 
 * DESCRIPTION: 
 * 
 ***********************************************************************/
package com.infodms.dms.actions; 
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener; 
import org.activiti.engine.ProcessEngine;
import org.activiti.engine.ProcessEngineConfiguration;
import org.activiti.engine.ProcessEngines;
import org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration; 
import com.infodms.dms.db.DBManager;
import com.infodms.dms.utils.DmsActivitiTransactionFactory; 
public class MyServletListener implements ServletContextListener { 
	@Override
	public void contextDestroyed(ServletContextEvent arg0) {
       ProcessEngines.destroy();
	} 
	@Override
	public void contextInitialized(ServletContextEvent arg0) {
	    StandaloneProcessEngineConfiguration conf = (StandaloneProcessEngineConfiguration) ProcessEngineConfiguration.createStandaloneProcessEngineConfiguration();
	    conf.setDataSource(DBManager.getDataSource()).setDatabaseSchemaUpdate("true").setDbHistoryUsed(true) ;
	    conf.setTransactionFactory(new DmsActivitiTransactionFactory()) ;
  	    ProcessEngine processEngine = conf.buildProcessEngine() ;   
    }
}

conf.setTransactionFactory(new DmsActivitiTransactionFactory()) ;设置事物

DmsActivitiTransactionFactory代码如下：

/********************************************************************** 
 *  
 * FILE : DmsActivitiTransactionFactory.java 
 * CLASS : DmsActivitiTransactionFactory 
 * 
 * AUTHOR : Liaokailin 
 * 
 * FUNCTION :  
 * 
 * 
 * Contact: Sina L凯林 
 * 
 *====================================================================== 
 * CHANGE HISTORY LOG 
 *---------------------------------------------------------------------- 
 * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ. 
 *---------------------------------------------------------------------- 
 * 		    |2014年1月21日|Liaokailin| Created | 
 * DESCRIPTION: 
 * 
 ***********************************************************************/
package com.infodms.dms.utils; 
import java.sql.Connection;
import java.util.Properties; 
import org.apache.ibatis.transaction.Transaction;
import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory; 
import com.infoservice.po3.core.context.DBService; 
public class DmsActivitiTransactionFactory extends JdbcTransactionFactory { 
	@Override
	public Transaction newTransaction(Connection conn, boolean autoCommit) {
		System.out.println("开启新的事物");
		 return new DmsActitiviTransaction(conn,autoCommit) ;
		//return (Transaction) DBService.getInstance().getTransaction() ;
	} 
	@Override
	public void setProperties(Properties props) {
		super.setProperties(props);
	} 
}

DmsActitiviTransaction 代码如下：

/********************************************************************** 
 *  
 * FILE : DmsActitiviTransaction.java 
 * CLASS : DmsActitiviTransaction 
 * 
 * AUTHOR : Liaokailin 
 * 
 * FUNCTION :  
 * 
 * 
 * Contact: Sina L凯林 
 * 
 *====================================================================== 
 * CHANGE HISTORY LOG 
 *---------------------------------------------------------------------- 
 * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ. 
 *---------------------------------------------------------------------- 
 * 		    |2014年1月21日|Liaokailin| Created | 
 * DESCRIPTION: 
 * 
 ***********************************************************************/
package com.infodms.dms.utils; 
import java.sql.Connection;
import java.sql.SQLException; 
import org.apache.ibatis.transaction.jdbc.JdbcTransaction; 
import com.infodms.dms.db.DBManager;
import com.infoservice.po3.core.context.DBService; 
public class DmsActitiviTransaction extends JdbcTransaction {
    private static Connection conn = null ;
	public DmsActitiviTransaction(Connection connection,
			boolean desiredAutoCommit) {
		//connection.setAutoCommit(desiredAutoCommit);
	 super(connection, desiredAutoCommit);
	 try {
		connection.setAutoCommit(desiredAutoCommit);
	} catch (SQLException e) {
		e.printStackTrace();
	} 
	} 
	@Override
	public Connection getConnection() {
		/*DBService d = DBService.getInstance() ;
		d.loadConf("/DataAccessContext.xml");
		return d.getConnection() ;*/
	  //	 return DBService.getInstance().getConnection() ;
		try {
			if(conn==null){
				synchronized (DmsActitiviTransaction.class) {
					conn = DBManager.getConnection() ;
				}
			}
			return conn ;
		} catch (Exception e) {
			System.out.println("获取链接失败："+e);
			return null ;
		}
	} 
	@Override
	public void close() throws SQLException {
	/*	if(conn!=null&&!conn.isClosed()){
			conn.close();
		}*/
		System.out.println("activit:close()");
	} 
	@Override
	public void commit() throws SQLException {
		/*if(conn!=null&&!conn.isClosed()){
			conn.commit();
		}*/
		System.out.println("activit:commit()");
	} 
	@Override
	protected void resetAutoCommit() {
		System.out.println("resetAutoCommit()");
		/*try {
			if (conn != null && !conn.isClosed()) {
				conn.setAutoCommit(false);
			}
		} catch (SQLException e) {
			e.printStackTrace(); 
		}*/
	} 
	@Override
	public void rollback() throws SQLException {
		/*if(conn!=null&&!conn.isClosed()){
			conn.rollback();
		}*/
		System.out.println("activit:rollback()");
	} 
	@Override
	protected void setDesiredAutoCommit(boolean arg0) {
		System.out.println("setDesiredAutoCommit:"+arg0);
	} 
}

其中DBManager

/********************************************************************** 
 *  
 * FILE : DBManager.java 
 * CLASS : DBManager 
 * 
 * AUTHOR : Liaokailin 
 * 
 * FUNCTION :  
 * 
 * 
 * Contact: Sina L凯林 
 * 
 *====================================================================== 
 * CHANGE HISTORY LOG 
 *---------------------------------------------------------------------- 
 * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ. 
 *---------------------------------------------------------------------- 
 * 		    |2014年1月22日|Liaokailin| Created | 
 * DESCRIPTION: 
 * 
 ***********************************************************************/
package com.infodms.dms.db; 
import java.sql.Connection;
import java.sql.SQLException; 
import javax.sql.DataSource; 
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource; 
import com.infoservice.po3.core.context.DBInfo; 
public class DBManager {
    public static DataSource dataSource = null  ;
    public static Connection conn = null ;
	public static DataSource getDataSource(){
		    if(dataSource==null){
		    	synchronized (DBManager.class) {
		    		Resource resource = new ClassPathResource("/DataAccessContext.xml");
				    BeanFactory springBeanFactory = new XmlBeanFactory(resource);
				    DBInfo dbInfo = ((DBInfo)springBeanFactory.getBean("DBInfo"));
				    dataSource = (DataSource)springBeanFactory.getBean(dbInfo.getDefDataSource());
				    System.out.println("获取数据源");
				}
		    }else{
		    	System.out.println("默认数据源调用");
		    } 
		return dataSource ;
	} 
	public static Connection getConnection() throws SQLException{
		if(conn!=null&&!conn.isClosed()){
			System.out.println("获取默认连接"); 
		}else{
			synchronized (DBManager.class) {
				System.out.println("获取连接");
				conn = getDataSource().getConnection() ;
			}
		}
		return conn ;
	} 
	public static void startTransaction(Connection connection) throws SQLException {
		System.out.println("开启事物");
		connection.setAutoCommit(false);
	} 
	public static void endTransaction(Connection connection) throws SQLException{
		System.out.println("提交事物 ");
		connection.commit();
		connection.setAutoCommit(true);
	} 
	public static void rollBack(Connection connection) throws SQLException{
		System.out.println("回滚事物");
		connection.rollback();
	}
}

调用的使用DBManager就ok了

原创文章，作者：奋斗，如若转载，请注明出处：https://blog.ytso.com/7767.html

工作流activiti-02事物控制、流程引擎创建详解编程语言

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