学习(fn)使用struts+hibernate实现一个通用的分늨序?/span>
内容Q?/span>
分页E序是网设计经帔R要实现的基本功能。但有的分页E序直接嵌在jsp面上，不仅工作量较大，代码也难以重用。本ơ试验将使用struts+hibernate来实现通用的分늨序。不同功能的代码量分离Q以满通用性要求?/span>
首先需要徏立一个表Q如下Product,各字D设计如?可自由更?Q?/span>
ID int primary key,
Typeid varchar(20),
Name varchar(50),
Price varchar(20),
Memo varchar(100).
步骤Q?/span>
1 建立web工程Q名字ؓ(f)”Fenye”.
2 dhibernateQ生?/span>Product表的.hbm.xml?/span>pojocR这个很单，不再赘述?/span>
3 接着写数据访问层Q我们将其分?/span>Dao?/span>ProDao两个cR其?/span>Dao是个公共的基c；ProDaol承它，q与action通信取得参数。这栯计的好处是：(x)如果需要对Userq个表进行分|C，只需d一?/span>UserDaoc，q让它?/span>DaocR?/span>
Daocȝ代码如下Q可以根据需要添加：(x)头文件自己导入?/span>
public class Dao {
private Session session=null;
public Dao() {
}
public Session getSession()
{
session = HibernateSessionFactory.getSession();
return session;
}
public int getCount(String pojo)
{
String sql="select count(*) from "+pojo ;
this.getSession();
try {
Query q = getSession().createQuery(sql);
List cc = q.list();
Integer rows = (Integer) cc.get(0);
return rows.intValue();
} catch (HibernateException ex) {
System.out.print("ex::"+ex.getMessage());
return 0;
}
}
public List getlist(Query query, String pojo,int pagesize,int currow) throws HibernateException
{
List list = null;
this.getSession();
query.setFirstResult(currow);
query.setMaxResults(pagesize);
list=query.list();
//session.flush();
if(session!=null)
session.close();
return list;
}
public List getlist(Query query,int pagesize,int currow)
{
String[] str = query.getQueryString().split("from");
String[] table =str[1].trim().split(" ");
System.out.println("table:"+table[0]);
return getlist(query,table[0],pagesize,currow);
}
}
ProDaocȝ代码如下Q?/span>
public class PinfoDao extends Dao{
private Session session;
public PinfoDao() {
super();
}
public List list(int pagesize,int currow)
{
Query query =getSession().createQuery("from PInfo");
List li=getlist(query, pagesize, currow);
return li;
}
public Session getSession()
{
// Configuration config=null;
session = HibernateSessionFactory.getSession();
return session;
}
public int getCount()
{
String sql="select count(*) from PInfo";
Query q = getSession().createQuery(sql);
List cc = q.list();
Integer a = (Integer) cc.get(0);
System.out.println("count:"+a.intValue());
return a.intValue();
}
}
4 下面写页面控制程序，同样代码分Mؓ(f)两个c?/span>PagecdPagehelpcR?/span>
Pagecd理页面相关的一些设|，如一|C多条记录Q计共有多页Q共有多记录，当前늠{?/span>
PageHelpcL?/span>jsp面传来的参敎ͼq调?/span>Pagecd理?/span>
PagecM码：(x)
public class Page {
private int totalRows; //总行?/span>
private int pageSize = 3; //每页昄的行?/span>
private int currentPage; //当前号
private int totalPages; //总页?/span>
private int startRow; //当前在数据库中的v始行
public Page(int totalRows1) {
totalRows = totalRows1;
totalPages=totalRows/pageSize;
int mod=totalRows%pageSize;
if(mod>0){
totalPages++;
}
currentPage = 1;
startRow = 0;
}
public int getStartRow() {
return startRow;
}
public int getTotalPages() {
return totalPages;
}
public int getCurrentPage() {
return currentPage;
}
public int getPageSize() {
return pageSize;
}
public void setTotalRows(int totalRows) {
this.totalRows = totalRows;
}
public void setStartRow(int startRow) {
this.startRow = startRow;
}
public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getTotalRows() {
return totalRows;
}
public void first() {
currentPage = 1;
startRow = 0;
}
public void previous() {
if (currentPage == 1) {
return;
}
currentPage--;
startRow = (currentPage - 1) * pageSize;
}
public void next() {
if (currentPage < totalPages) {
currentPage++;
}
startRow = (currentPage - 1) * pageSize;
}
public void last() {
currentPage = totalPages;
startRow = (currentPage - 1) * pageSize;
}
public void refresh(int _currentPage) {
currentPage = _currentPage;
if (currentPage > totalPages) {
last();
}
}
}
PagehelpcM码如下：(x)
public class Pagehelp {
public static Page getPager(HttpServletRequest httpServletRequest,int totalRows) {
//定义pager对象Q用于传到页?/span>
Page pager = new Page(totalRows);
//?/span>Request对象中获取当前页?/span>
String currentPage = httpServletRequest.getParameter("currentPage");
//如果当前号为空Q表CZؓ(f)首次查询该页
//如果不ؓ(f)I，则刷?/span>page对象Q输入当前页L(fng)信息
if (currentPage != null) {
pager.refresh(Integer.parseInt(currentPage));
}
//获取当前执行的方法，首页Q前一，后一，N?/span>
String pagerMethod = httpServletRequest.getParameter("pageMethod");
if (pagerMethod != null) {
if (pagerMethod.equals("first")) {
pager.first();
} else if (pagerMethod.equals("previous")) {
pager.previous();
} else if (pagerMethod.equals("next")) {
pager.next();
} else if (pagerMethod.equals("last")) {
pager.last();
}
}
return pager;
}
}
5 一切准备工作结束后Q下面写action来调用这些类?/span>
List list = null;//用于输出到页面的记录集合
int totalRows;//记录总行?/span>
PinfoDao dao=new PinfoDao();
totalRows=dao.getCount();
System.out.print("总行?/span>=="+totalRows);
Page page=Pagehelp.getPager(request,totalRows);
try {
list= dao.list(page.getPageSize(), page.getStartRow());
} catch (HibernateException ex) {
System.out.print("action里的错误="+ex.getMessage());
}
request.setAttribute("page",page);
request.setAttribute("list",list);
return mapping.findForward("list");
6 最后是昄面plist。在struts-config.xml文g中添?/span>forward语句Q?/span><forward name="list" path="/plist.jsp"></forward>?/span>
plist.jsp面部分代码如下Q?/span>
<table align="center" border="1">
<tr>
<td>产品cd</td>
<td>产品名称</td>
<td>产品h</td>
<td>产品备注</td>
</tr>
<!?/span>下面打印list中的各属?/span>-->
<tr >
<td colspan="4">
W?/span><bean:write name="page" property="currentPage"/>?/span>
?/span><bean:write name="page" property="totalPages" />?/span>
<html:link action="/page.do?pageMethod=first"
paramName="page" paramProperty="currentPage"
paramId="currentPage">首页</html:link>
<html:link action="/page.do?pageMethod=previous"
paramName="page" paramProperty="currentPage"
paramId="currentPage">上一?/span></html:link>
<html:link action="/page.do?pageMethod=next"
paramName="page" paramProperty="currentPage"
paramId="currentPage">下一?/span></html:link>
<html:link action="/page.do?pageMethod=last"
paramName="page" paramProperty="currentPage"
paramId="currentPage">N</html:link>
</td>
</tr>
</table>
7 试Q?/span>
按照上述步骤完成后，在浏览器中输?/span>http://localhost:8080/Fenye/page.do查看面?/span>
]]>
<%@ page import="java.sql.*,javax.sql.*,javax.naming.*" %>
<html>
<head>
<title>|上书店留言?lt;/title>
</head>
<body>
<a href="say.html">我要留言</a><br>
<%
Context ctx=new InitialContext();
DataSource ds=(DataSource)ctx.lookup("java:comp/env/jdbc/bookstore");
Connection conn=ds.getConnection();
//创徏可滚动的l果集?br />
Statement stmt=conn.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
ResultSet rs=stmt.executeQuery("select * from guestbook order by gst_time desc");
//Ud游标到结果集的最后一行?br />
rs.last();
//得到当前行的行数Q也得C(jin)数据库中留言的L?br />
int rowCount=rs.getRow();
if(rowCount==0)
{
out.println("当前没有M留言!");
return;
}
String strCurPage=request.getParameter("page");
//表示当前的页数?br />
int curPage;
if(strCurPage==null)
curPage=1;
else
curPage=Integer.parseInt(strCurPage);
//定义每页昄的留a数?br />
int countPerPage=5;
//计算昄所有留a需要的总页数?br />
int pageCount=(rowCount+countPerPage-1)/countPerPage;
//Ud游标到结果集中指定的行。如果显C的是第一，curPage=1Q?br />
//游标Ud到第1行?br />
rs.absolute((curPage-1)*countPerPage+1);
//如果是第1，则显CZ带链接的文字Q如果不是第1，
//则给用户提供跌{到第一和上一늚链接?br />
if(curPage==1)
{
%>
W一?amp;nbsp;
上一?amp;nbsp;
<%
}
else
{
%>
<a href="index.jsp?page=<%=1%>">W一?lt;/a>
<a href="index.jsp?page=<%=curPage-1%>">上一?lt;/a>
<%
}
//如果当前|最后一，则显CZ带链接的文字Q如果不是最后一，
//则给用户提供跌{到最后一和下一늚链接?br />
if(curPage==pageCount)
{
%>
下一?amp;nbsp;
最后页
<%
}
else
{
%>
<a href="index.jsp?page=<%=curPage+1%>">下一?lt;/a>
<a href="index.jsp?page=<%=pageCount%>">最后页</a>
<%
}
int i=0;
//以@环的方式取出每页要显C的数据Q因为在前面针对要显C的|Q?br />
//调用?jin)rs.absolute((curPage-1)*countPerPage+1);
//所以是从游标所在的位置取出当前要昄的数据?br />
while(i<countPerPage && !rs.isAfterLast())
{
out.println("<hr color=\"blue\" size=\"2\"><br>");
out.println("用户名：(x)"+rs.getString("gst_user"));
out.println(" ");
Timestamp ts=rs.getTimestamp("gst_time");
long lms=ts.getTime();
Date date=new Date(lms);
Time time=new Time(lms);
out.println("留言旉Q?+date+" "+time);
out.println(" ");
out.println("用户IPQ?+rs.getString("gst_ip")+"<br>");
out.println("主题Q?+rs.getString("gst_title")+"<br>");
out.println("内容Q?+rs.getString("gst_content"));
i++;
rs.next();
}
rs.close();
stmt.close();
conn.close();
%>
</body>
</html>
]]>