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[Java教程]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.

<?"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.

<!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.

 

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.

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");  }}

<??><web-app version="2.5"   ="http://java.sun.com/   ="http://www.w3.org/2001/   xsi:schemaLocation="http://java.sun.com/>             <!--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>