工作流activiti-02事物控制、流程引擎创建

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）

/**********************************************************************
 * <pre>
 * 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:
 * </pre>
 ***********************************************************************/
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：

/**********************************************************************
 * <pre>
 * 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:
 * </pre>
 ***********************************************************************/
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：

/**********************************************************************
 * <pre>
 * 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:
 * </pre>
 ***********************************************************************/
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

/**********************************************************************
 * <pre>
 * 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:
 * </pre>
 ***********************************************************************/
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