J2EE DAO模式解析（三）

        我们先看一下界面

       

<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>
<%
	String path=request.getContextPath();
	String basePath=request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<html>
	<head>
       <base href="<%=basePath %>">
		<meta http-equiv="Content-Type" content="text/html; charset=GB18030">
		<title>添加流向单维护</title>
</head>
<body>
	<form name="flowCardAddForm" method="post" action="servlet/flowcard/FlowCardServlet" >
       <input type="hidden" name="command" value="add">
       <input type=”submit” id=”btnAdd” value=”添加”/>
    </form>
</body>
</html>


        下面看一下Servlet

         

public class FlowCardServlet extends HttpServlet {
    private FlowCardManager flowCardManager;
	public void init() throws ServletException {
		flowCardManager=(FlowCardManager)getBeanFactory().getServiceObject(FlowCardManager.class);
	}
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {
       add(request,response);
}
private void add(HttpServletRequest request,HttpServletResponse response)
	 throws ServletException,IOException
	 {
		 /**
         ***调用业务逻辑层代码之前的准备代码***
		 */
		 //通过工厂取得业务逻辑对象
		 FlowCardManager flowCardManager=(FlowCardManager)getBeanFactory().getServiceObject(FlowCardManager.class);
	flowCardManager.addFlowCard(flowCard);		 response.sendRedirect(request.getContextPath()+"/flowcard/flow_card_maint.jsp");
	 }
protected BeanFactory getBeanFactory()
	{
        BeanFactory beanFactory=BeanFactory.getInstance();
		return beanFactory;
	}
}


        下面看一下业务逻辑层

        

public interface FlowCardManager {
   public void addFlowCard(FlowCard flowCard) throws ApplicationException;
}
public class FlowCardManagerImpl implements FlowCardManager {
	private FlowCardDao flowCardDao;

	public FlowCardManagerImpl()
	{
		this.flowCardDao=(FlowCardDao)BeanFactory.getInstance().getDaoObject(FlowCardDao.class);
	}
public void addFlowCard(FlowCard flowCard) throws ApplicationException {
    Connection conn=null;
		try{
			//取得Connection
			conn=ConnectionManager.getConnection();
			//开始事务
			ConnectionManager.beginTransaction(conn);
			//添加前的准备工作，给参数赋值***************省略
			//添加流向单主信息
			flowCardDao.addFlowCardMaster(flowCardVouNo, flowCard);
			
			//提交事务
			ConnectionManager.commitTransaction(conn);
		}catch(DaoException e)
		{
			//回滚事务
			ConnectionManager.rollbackTransaction(conn);
			throw new ApplicationException("添加流向单失败");
		}finally
		{
			//关闭Connection并从ThreadLocal清除
			ConnectionManager.closeConnection();
		}
}
}

        最后Dao层

        

public interface FlowCardDao {
	
	/**
	 * 添加流向单主信息
	 * @param flowCardVouNo
	 * @param flowCard
	 */
	public void addFlowCardMaster(String flowCardVouNo,FlowCard flowCard);
}
public class FlowCardDaoImpl implements FlowCardDao {
		@Override
	public void addFlowCardMaster(String flowCardVouNo, FlowCard flowCard) {
		StringBuffer sbSql=new StringBuffer();
		sbSql.append("……………省略…………………..");
		PreparedStatement pstmt=null;
		try{
			Connection conn=ConnectionManager.getConnection();
			pstmt=conn.prepareStatement(sbSql.toString());
			pstmt.setString(…为sql语句中需要的参数赋值……….);
			pstmt.executeUpdate();
		}catch(SQLException e){
			e.printStackTrace();
			System.out.println("FlowCardDaoImpl-->>addFlowCardMater,exception:"+e);
			throw new DaoException(e);
			
		}finally{
			ConnectionManager.close(pstmt);  //此处并没有关闭connection
		}

	}
}

           整个DAO模式就是这样子了。


 

posted @ 2012-03-15 16:57  转航  阅读(225)  评论(0)    收藏  举报