package com.orizone.oa.extra.service;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import net.orizone.oa.common.ConnectionPoolBean;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.orizone.comm.util.BusinessException;

public class TransactionUtil
{
 private final static ThreadLocal local = new ThreadLocal();
 private static Log log = LogFactory.getLog(TransactionUtil.class);
 
 /**
  * 开启事务
  */
 public static void startTransaction()throws  BusinessException
 {
  Transaction tran = (Transaction)local.get();
  //判断此事务是否属于一个顶层事务。
  if(tran == null)
  {
   tran = new Transaction();
   //设置本地线程的connection
   Connection con = ConnectionPoolBean.getConnection();
   try
   {
    con.setAutoCommit(false);
   }catch(SQLException e)
   {
    e.printStackTrace();
    throw new BusinessException(e, "开启事务失败！");
   }
   tran.setConnection(con);
   tran.setCommitCount(0);
   tran.setTransCount(1);
   tran.setTransDeep(1);
   
   local.set(tran);
  }else
  {
   //事务已经开启，将嵌套层次深度加一，将事务次数加一
   tran.setTransCount(tran.getTransCount() + 1);
   tran.setTransDeep(tran.getTransDeep() + 1);
  }  
 }
 
 /**
  * 提交事务
  *
  */
 public static void commitTransaction()throws  BusinessException
 {
  Transaction tran = (Transaction)local.get();
  //如果事务属于嵌套，则不提交数据，直接将层次数减一。
  if(tran.getTransDeep() > 1)
  {
   tran.setTransDeep(tran.getTransDeep() - 1);
   tran.setCommitCount(tran.getCommitCount() + 1);
   return;
  }
  
  Connection con = tran.getConnection();
  try
  {
   if(tran.hasFullExecute())
   {
    con.commit();   
   }
  }catch(SQLException e)
  {
   log.error(e);   
   throw new BusinessException(e, "提交事务失败!");
  }
 }
 
 /**
  * 结束事务
  *
  */
 public static void endTransaction()throws  BusinessException
 {
  Transaction tran = (Transaction)local.get();
  //如果事务属于嵌套，则不关闭连接，直接将层次数减一。
  if(tran.getTransDeep() > 1)
  {
   tran.setTransDeep(tran.getTransDeep() - 1);
   return;
  }
  
  //当前事务已经结束，清空ThreadLocal变量，防止下一次操作拿到已经关闭的Connection对象。
  local.set(null);
  Connection con = tran.getConnection();
  try
  {
   if(!tran.hasFullExecute())
   {
    con.rollback();
   }
  }catch(SQLException e)
  {
   log.error(e);
   throw new BusinessException(e, "事务回滚失败!");
  }finally
  {
   try
   {
    con.close();
   }catch(SQLException se)
   {
    log.error(se);
    throw new BusinessException(se, "关闭事务失败!");
   }
  }
  
 }
 
 /**
  * 获取当前事务的数据库连接。
  * @return
  */
 public static Connection getConnection()
 {
  Transaction tran = (Transaction)local.get();
  Connection  con = tran.getConnection();
  if(con == null)
  {
   con = ConnectionPoolBean.getConnection();   
  }
  return con;
 }
 
 /**
  * 测试代码
  * @param args
  * @throws Exception
  */
 public static void main(String args[])throws Exception
 {
  test();
  test();
 }
 
 /**
  * 测试代码
  *
  */
 private static void test()
 {
  TransactionUtil.startTransaction();
  try
  {
   Connection con = TransactionUtil.getConnection();
   Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
   stmt.executeUpdate("INSERT INTO bb(bb) values('bb')");
   stmt.executeUpdate("INSERT INTO aa(aa) values('aa')");
   //if(true) throw new Exception("");
   TransactionUtil.commitTransaction();
  }catch(Exception e)
  {
   e.printStackTrace();
   //throw new BusinessException("");
  }finally
  {
   TransactionUtil.endTransaction();
  }
 }
}

package com.orizone.oa.extra.service;

import java.sql.Connection;

public class Transaction
{
 //数据库连接对象
 private Connection connection;
 //事务次数
 private int transCount;
 //提交次数
 private int commitCount;
 //事务嵌套层次
 private int transDeep;

 int getCommitCount()
 {
  return commitCount;
 }

 void setCommitCount(int commitCount)
 {
  this.commitCount = commitCount;
 }

 Connection getConnection()
 {
  return connection;
 }

 void setConnection(Connection conn)
 {
  this.connection = conn;
 }

 public int getTransCount()
 {
  return transCount;
 }

 void setTransCount(int transCount)
 {
  this.transCount = transCount;
 }

 int getTransDeep()
 {
  return transDeep;
 }

 void setTransDeep(int transDeep)
 {
  this.transDeep = transDeep;
 }
 
 /**
  * 判断事务是否完全提交。
  * 通过提交次数和事务次数来判断事务是否完全提交。
  * @return
  */
 boolean hasFullExecute()
 {
  return commitCount + 1 == transCount;
 }

}