在 Servlet 上调用 DAO 方法答案

【问题标题】：Invoking a DAO method on a Servlet在 Servlet 上调用 DAO 方法
【发布时间】：2014-09-19 02:46:43
【问题描述】：

我正在制作网页，用户可以通过rentID搜索租用的产品，在Servlet中我想调用一个DAO方法来根据该rentID查找租用的产品，如果租金是，则将用户重定向到新网页找到与否。

这是用户通过 ID 搜索产品的 JSP

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org   /TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h3>Find Rent</h3><br>

<form  action="FindRent" method="GET">
<fieldset>
<p>
<label for="id">Rent ID</label>
<input type="text" name="id"/>
</p>
<p>
<input type="submit" value="Search" />
</p>
</fieldset>

</form>

</body>
</html>

这是 DAO 实现。

public class RentHibernateDao implements RentDao {

@Override
public void saveRent(Rent rent) {

    SessionFactory factory = 
            HibernateUtil.getSessionFactory();
        Session session = factory.openSession();

        session.getTransaction().begin();

         session.save(rent);

        session.getTransaction().commit();
        session.close();

}

@Override
public Rent find(Integer rentId) {
    SessionFactory factory = 
            HibernateUtil.getSessionFactory();
        Session session = factory.openSession();

        session.getTransaction().begin();

        Rent rent=(Rent)session.get(Rent.class, rentId);
        session.close();
    return rent;
}

@Override
public void EndRent(Integer rentId) {

    SessionFactory factory = 
            HibernateUtil.getSessionFactory();
        Session session = factory.openSession();

        session.getTransaction().begin();

        Rent rent=this.find(rentId);
        rent.setRealReturnDate(new Date());
        rent.getProduct().changeStatus();
        session.saveOrUpdate(rent);
        session.getTransaction().commit();
        session.close();


    }

这就是 Servlet。如何调用该方法？

public class FindRent extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
 * @see HttpServlet#HttpServlet()
 */
public Rent find() {
    super();
    // TODO Auto-generated constructor stub
}

/**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

【问题讨论】：

嗯，创建 RentHibernateDao 对象，并调用适当的方法，根据需要返回 HTML。

标签： java hibernate jsp servlets dao

【解决方案1】：

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    int rentId= Integer.parseInt(request.getParameter("id"));       // capture the rent id
    RentDao dao= new RentHibernateDao();        // create the dao object
    dao.find(rentId);   // If successful, it returns you an object of Rent class
   // means Id is there
  // put your processing logic here
    request.getRequestDispatcher("desiredpage.jsp").forward(request, response);         // forward to your desired page

   }

【讨论】：