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 = ;
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 == )? (allRows / pageSize): (allRows / pageSize) + ; 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 - ); 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 == )? : 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(, 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="">
<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")[].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="" 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="">共<font color="red"><s:property value="#request.pageBean.totalPage"/></font>页 </font>
<font size="">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 上一页
</s:if> <s:else>
<a href="personAction.action">首页</a>
<a href="personAction.action?page=<s:property value="#request.pageBean.currentPage - "/>">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 + "/>">下一页</a>
<a href="personAction.action?page=<s:property value="#request.pageBean.totalPage"/>">尾页</a>
</s:if> <s:else>
下一页 尾页
</s:else> </center><br> <center> <form action="personAction" onsubmit="return validate();">
<font size="">跳转至</font>
<input type="text" size="" 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: