Java_Web三大框架之Hibernate+jsp+selvect+HQL查询数据

俗话说："好记性不如烂笔头"。本人学习Hibernate也有一个星期了，对Hibernate也有一个初步的了解。下面对Hibernate显示数据做个笔记，使用租房系统的Hibernate+jsp+selvect。

第一步：编写房屋实体类

/*
 * 房屋实体类
 */

public class House {
    private int id;//房屋id
        private String title;//标题
    private String description;//描述
    private String fdate;//日期
    private String price;//价格
    private String contact;//面积

       //省略get和set方法
}

第二步：配置House.hbm.xml映射

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping
    package="entity">

    <class name="House" table="House">
        <id name="id">
            <generator class="increment"/>
        </id>
 
        <property name="title" />
        <property name="description" />
        <property name="fdate" />
        <property name="price" />
        <property name="contact" />

        
    </class>

</hibernate-mapping>

第三步：配置hibernate.cfg.xml数据库映射（别忘了导入hibernate必备的架包）

<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory name="foo">
        <!-- 数据库方言 -->
        <property name="dialect">
            org.hibernate.dialect.OracleDialect
        </property>
        <!-- 连接数据库Url -->
        <property name="hibernate.connection.url">
            jdbc:oracle:thin:@localhost:1521:orcl
        </property>
        <!-- 连接驱动 -->
        <property name="hibernate.connection.driver_class">
            oracle.jdbc.driver.OracleDriver
        </property>
        <!-- 用户名 -->
        <property name="hibernate.connection.username">epet</property>
        <!-- 密码 -->
        <property name="hibernate.connection.password">123456</property>

                <!-- 在控制台打印sql信息 -->
        <property name="show_sql">true</property>
        <!-- 创建表结构 -->
        <property name="hibernate.hbm2ddl.auto">update</property>
    
        <!-- 配置映射信息 -->
    
        <mapping resource="entity/House.hbm.xml" />
        
        
    </session-factory>
</hibernate-configuration>

第四步：编写dao层和daoImpl层

/*
 * 查询所有房屋
 */
public interface HouseDao {
    /*
     * 查询所有房屋
     */
    public List<House> selecthouse();
    

}

public class HouseDaoImpl implements HouseDao{

/*
 * 查询所有房屋
 * 
 * (non-Javadoc)
 * @see Dao.HouseDao#selecthouse()
 */
    public List<House> selecthouse() {
        // TODO Auto-generated method stub
         Session session = HibernateUtil.getSession();

              //查询房屋实体类
         String hql="from House";
         Query q=session.createQuery(hql);
         
          List<House> list = q.list();

          return list;
      
    }
}
注意：Hibernate查询的实体，而不是数据库表

第五步：编写Selvect和web.xml配置

package selvect;



import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import entity.House;

import Biz.HouseBiz;
import Biz.Impl.HouseBizImpl;



public class SelectAllServlet extends HttpServlet {

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        System.out.println("销毁select");
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request,response);
//        response.setContentType("text/html");
//        PrintWriter out = response.getWriter();
//        out.println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
//        out.println("<HTML>");
//        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
//        out.println("  <BODY>");
//        out.print("    This is ");
//        out.print(this.getClass());
//        out.println(", using the GET method");
//        out.println("  </BODY>");
//        out.println("</HTML>");
//        out.flush();
//        out.close();
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
    
        HouseBiz mb=new HouseBizImpl();
        
        List<House> li=mb.selecthouse();
        request.getSession().setAttribute("li", li);
        response.sendRedirect("list.jsp");
    
        //request.getRequestDispatcher("index.jsp").forward(request, response);
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        System.out.println("初始化servlet");
    }

}

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    

  
                    <!--查询房屋-->
    <servlet>
    <servlet-name>SelectAllServlet</servlet-name>
    <servlet-class>selvect.SelectAllServlet</servlet-class>
    </servlet>
    
  <!-- 映射servlet -->
  <servlet-mapping>
      <servlet-name>SelectAllServlet</servlet-name>
      <url-pattern>/SelectAllServlet</url-pattern>
  </servlet-mapping>
  
      

  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

在jsp页面显示

        <LI class=bold>房屋信息</LI>    
<c:forEach var="mind" items="${sessionScope.li}">
  <TR>
    <TD class=house-thumb><span><A href="details.htm" target="_blank"><img src="images/thumb_house.gif" width="100" height="75" alt=""></a></span></TD>
    <TD>

  
      <DL>
  <!--标题，价格-->
        <DT><A href="houseid?id=${mind.id}" target="_blank">${mind.title}</A></DT>
         

    <TD class=house-price><SPAN>${mind.price}</SPAN>元/月</TD></TR>
     
 
  </c:forEach>