/**
* Second scenario:transaction is rare
* we control connection inside service classes.
*/
/**
* -----ConnectionManager.class---------
*/
public static Connection getConnection()
{
return getConnection(ModuleConfig.getDefaultJndi());
}
public static Connection getConnection(final String jndi)
{
Connection conn = null;
try
{
DataSource ds = dsMap.get(jndi);
if(ds==null) return null;
conn = ds.getConnection();
conn.setAutoCommit(true);
}
catch(SQLException sqle)
{
SysLogger.error("Database fail to get connection 1",sqle);
}
catch(Exception sqle)
{
SysLogger.error("Database fail to get connection 2",sqle);
}
return conn;
}
public static void rollback(Connection conn)
{
try
{
if(conn==null || conn.isClosed())
return;
if(!conn.getAutoCommit())
conn.rollback();
}
catch(SQLException se)
{
SysLogger.error("Can not do rollback operation.",se);
}
}
}
/**
* -----ActionServlet.class---------
*/
private void processHttpRequest(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html;charset=GB2312");
request.setCharacterEncoding("GB2312");
String beanId = extractBeanID(request.getRequestURI());
String methodName = request.getParameter("method");
String targetJsp = null;
if(beanId==null || methodName==null)
{
request.setAttribute(EXCEPTION_MESSAGE,"请求URI错误.");
forward(request,response,targetJsp);
return;
}
BaseAction ba = BeanFactory.newAction(beanId);
BaseService bs = BeanFactory.newService(beanId);
if(ba==null || bs == null)
{
request.setAttribute(EXCEPTION_MESSAGE,"没有Bean为" + beanId + "的action或service");
forward(request,response,targetJsp);
return;
}
ActionAnnotation ann = AnnotationExtractor.getAnnotation(ba.getClass(), methodName);
ba.setRequest(request);
ba.setService(bs);
Method method = SysUtil.lookupMethod(ba.getClass().getMethods(),methodName);
Connection conn = null;
if(ann.isNeedDB())
{
conn = ConnectionManager.getConnection();
bs.setConnection(conn);
bs.setDao(BeanFactory.newDao(beanId,conn));
}
if(method!=null)
{
try
{
targetJsp = (String)method.invoke(ba);
}
catch(Exception e)
{
SysLogger.error("Error:" + bs.getClass().getName() + "." + method.getName(),e);
targetJsp = null;
}
}
if(ann.isNeedDB())
ConnectionManager.close(conn);
forward(request,response,targetJsp);
}
/**
* example:method in service class
* operating conncetion in service
*/
/**
* 这是两个dao实现一个事处的最好例子
*/
public void addTop(MenuDto dto) throws Exception
{
Connection conn = getConnection();
try
{
conn.setAutoCommit(false);
MenuDao mDao = new MenuDao(conn);
MenuRoleDao mrDao = new MenuRoleDao(conn);
MenuDto menu = mDao.getNextMenu();
menu.setTitle(dto.getTitle());
mDao.save(menu);
mrDao.saveMenu(menu.getId());
conn.commit();
}
catch(Exception e)
{
ConnectionManager.rollback(conn);
throw e;
}
}