使用hibernate和struts2实现分页功能

想着每天能学个新东西，今天准备了这个hibernate+struts2实现页面的分页功能，在这里，首先要感谢

http://www.blogjava.net/rongxh7/archive/2008/11/29/243456.html

这位博友发表的博文，通过对他代码的阅读，从而自己实现了网页分页功能，以下是源代码，如大家有需要，可以回复我，我会放出源代码供大家下载！

1.DAO层接口的设计，定义一个PersonDAO接口，里面声明了两个方法：

public interface PersonDAO{    public List<Person> queryByPage(String hql, int offset, int pageSize);        public int getAllRowCount(String hql);}

2.DAO层接口的实现类PersonDAOImpl类，将其两个方法实现出来：

public class PersonDAOImpl implements PersonDAO{    /**     * 通过hql语句得到数据库中记录总数     */    @Override    public int getAllRowCount(String hql)    {        Session session = HibernateUtil.openSession();        Transaction tx = null;        int allRows = 0;        try        {            tx = session.beginTransaction();                        Query query = session.createQuery(hql);                        allRows = query.list().size();                        tx.commit();                    }        catch (Exception e)        {            if(tx != null)            {                tx.rollback();            }                        e.printStackTrace();        }        finally        {            HibernateUtil.closeSession(session);        }                return allRows;    }    /**     * 使用hibernate提供的分页功能，得到分页显示的数据     */    @SuppressWarnings("unchecked")    @Override    public List<Person> queryByPage(String hql, int offset, int pageSize)    {        Session session = HibernateUtil.openSession();        Transaction tx = null;        List<Person> list = null;                try        {            tx = session.beginTransaction();                        Query query = session.createQuery(hql).setFirstResult(offset).setMaxResults(pageSize);                        list = query.list();                        tx.commit();                    }        catch (Exception e)        {            if(tx != null)            {                tx.rollback();            }                        e.printStackTrace();        }        finally        {            HibernateUtil.closeSession(session);        }                        return list;    }}

3.定义了一个PageBean(每一页所需要的内容都存放在这个PageBean里面)，里面用来存放网页每一页显示的内容：

public class PageBean{    private List<Person> list; //通过hql从数据库分页查询出来的list集合        private int allRows; //总记录数        private int totalPage; //总页数        private int currentPage; //当前页    public List<Person> getList()    {        return list;    }    public void setList(List<Person> list)    {        this.list = list;    }    public int getAllRows()    {        return allRows;    }    public void setAllRows(int allRows)    {        this.allRows = allRows;    }    public int getTotalPage()    {        return totalPage;    }    public void setTotalPage(int totalPage)    {        this.totalPage = totalPage;    }    public int getCurrentPage()    {        return currentPage;    }    public void setCurrentPage(int currentPage)    {        this.currentPage = currentPage;    }        /**     * 得到总页数     * @param pageSize 每页记录数     * @param allRows  总记录数     * @return 总页数     */    public int getTotalPages(int pageSize, int allRows)    {        int totalPage = (allRows % pageSize == 0)? (allRows / pageSize): (allRows / pageSize) + 1;                return totalPage;    }        /**     * 得到当前开始记录号     * @param pageSize 每页记录数     * @param currentPage 当前页     * @return     */    public int getCurrentPageOffset(int pageSize, int currentPage)    {        int offset = pageSize * (currentPage - 1);                return offset;    }        /**     * 得到当前页， 如果为0 则开始第一页，否则为当前页     * @param page     * @return     */    public int getCurPage(int page)    {        int currentPage = (page == 0)? 1: page;                return currentPage;    }    }

4.Service层接口设计，定义一个PersonService接口，里面声明了一个方法，返回一个PageBean：

public interface PersonService{    public PageBean getPageBean(int pageSize, int page);}

5.Service层接口实现类PersonServiceImpl类，实现唯一的方法：

public class PersonServiceImpl implements PersonService{    private PersonDAO personDAO = new PersonDAOImpl();        /**     * pageSize为每页显示的记录数     * page为当前显示的网页     */    @Override    public PageBean getPageBean(int pageSize, int page)    {        PageBean pageBean = new PageBean();                String hql = "from Person";                int allRows = personDAO.getAllRowCount(hql);                int totalPage = pageBean.getTotalPages(pageSize, allRows);                int currentPage = pageBean.getCurPage(page);                int offset = pageBean.getCurrentPageOffset(pageSize, currentPage);                List<Person> list = personDAO.queryByPage(hql, offset, pageSize);                pageBean.setList(list);        pageBean.setAllRows(allRows);        pageBean.setCurrentPage(currentPage);        pageBean.setTotalPage(totalPage);                return pageBean;    }}

6.Action层设计，定义一个PersonAction：

public class PersonAction extends ActionSupport{    private PersonService personService = new PersonServiceImpl();        private int page;        public int getPage()    {        return page;    }    public void setPage(int page)    {        this.page = page;    }    @Override    public String execute() throws Exception    {        //表示每页显示5条记录，page表示当前网页        PageBean pageBean = personService.getPageBean(5, page);                HttpServletRequest request = ServletActionContext.getRequest();                request.setAttribute("pageBean", pageBean);                return SUCCESS;    }}

7.辅助类设计，HibernateUtil:

public class HibernateUtil{    private static SessionFactory sessionFactory;        static    {        sessionFactory = new Configuration().configure().buildSessionFactory();    }        public static Session openSession()    {        Session session = sessionFactory.openSession();                return session;    }        public static void closeSession(Session session)    {        if(session != null)        {            session.close();        }    }    }

8.最后也就是分页页面显示pagePerson.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'pagePerson.jsp' starting page</title>        <meta http-equiv="pragma" content="no-cache">    <meta http-equiv="cache-control" content="no-cache">    <meta http-equiv="expires" content="0">        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">    <meta http-equiv="description" content="This is my page">    <script type="text/javascript">            function validate()        {            var page = document.getElementsByName("page")[0].value;                            if(page > <s:property value="#request.pageBean.totalPage"/>)            {                alert("你输入的页数大于最大页数，页面将跳转到首页！");                                window.document.location.href = "personAction";                                return false;            }                        return true;        }        </script>  </head>    <body>    <h1><font color="blue">分页查询</font></h1><hr>        <table border="1" align="center" bordercolor="yellow" width="50%">            <tr>            <th>序号</th>            <th>姓名</th>            <th>年龄</th>        </tr>            <s:iterator value="#request.pageBean.list" id="person">            <tr>            <th><s:property value="#person.id"/></th>            <th><s:property value="#person.name"/></th>            <th><s:property value="#person.age"/></th>                </tr>        </s:iterator>        </table>        <center>            <font size="5">共<font color="red"><s:property value="#request.pageBean.totalPage"/></font>页 </font>&nbsp;&nbsp;        <font size="5">共<font color="red"><s:property value="#request.pageBean.allRows"/></font>条记录</font><br><br>                <s:if test="#request.pageBean.currentPage == 1">            首页&nbsp;&nbsp;&nbsp;上一页        </s:if>                <s:else>            <a href="personAction.action">首页</a>            &nbsp;&nbsp;&nbsp;            <a href="personAction.action?page=<s:property value="#request.pageBean.currentPage - 1"/>">上一页</a>        </s:else>                <s:if test="#request.pageBean.currentPage != #request.pageBean.totalPage">            <a href="personAction.action?page=<s:property value="#request.pageBean.currentPage + 1"/>">下一页</a>            &nbsp;&nbsp;&nbsp;            <a href="personAction.action?page=<s:property value="#request.pageBean.totalPage"/>">尾页</a>        </s:if>                <s:else>            下一页&nbsp;&nbsp;&nbsp;尾页        </s:else>        </center><br>        <center>                <form action="personAction" onsubmit="return validate();">            <font size="4">跳转至</font>            <input type="text" size="2" name="page">页            <input type="submit" value="跳转">        </form>            </center>      </body></html>

至此，hibernate+struts2实现网页分页功能代码部分就完毕了，像hibernate与struts的配置文件就不列出来了，那些都不是重点！

页面效果如下: