应用displaytag完成大数据量分页显示的例子
应用displaytag在struts中完成大数据量分页显示，Oracle数据库
JSP文件：
<%
@ taglib uri="/WEB-INF/displaytag.tld" prefix="disp"
%>
<
disp:table
name
="resultList"
export
="true"
pagesize
="100"
requestURI
="logQueryAction.do"
sort
="external"
id
="element"
partialList
="true"
size
="resultSize"
>
<
disp:column
property
="operdate"
title
="操作时间"
></
disp:column
>
<
disp:column
property
="pername"
title
="操作人员"
></
disp:column
>
<
disp:column
property
="opertype"
title
="操作类型"
></
disp:column
>
</
disp:table
>
name="resultList" 将记录集存在session或者request中的键值
export="true" 是否显示导出选项
pagesize="100" 每页显示100条数据
requestURI="logQueryAction.do" struts中action的名称，如果记录少，可以直接分页
sort="external" 外部排序
id="element" 表格id值，用于程序得相关的参数
partialList="true" 分段从数据库中读数据
size="resultSize" 记录的总条数，用于计算总页数
struts action:
String pageIndexName
=
new
org.displaytag.util.ParamEncoder(
"
element
"
).encodeParameterName(org.displaytag.tags.TableTagParameters.PARAMETER_PAGE); // 页数的参数名
int
pageSize
=
100
; //每页显示的条数
int
pageIndex
=
GenericValidator.isBlankOrNull(request.getParameter(pageIndexName))
?
0
:(Integer.parseInt(request.getParameter(pageIndexName))
-
1
); //当前页数String sqlCount
=
"
select count(*) from user_log a
"
; //用于统计总记录数的sql语句 String sql
=
"
select * from (select rownum as rid, t1.* from (select b.pername as pername,to_char(a.operdate,'yyyy-mm-dd hh24:mi:ss') as operdate,
"
+
"
decode(a.opertype,'D','删除','M','修改','其他') as opertype, a.hphm as hphm from user_log a,
"
+
"
(select asuser.userid as userid,nvl(asempmsg.pername,asuser.loginname) as pername from asuser,ASEMPMSG where asuser.perid=ASEMPMSG.perid(+)) b
"
+
"
where a.userid=b.userid
"
; //查询语句
//构造查询条件
StringBuffer sb
=
new
StringBuffer();
if
(logQueryForm.getCzrqStart()
!=
null
&&
!
""
.equals(logQueryForm.getCzrqStart()))
{
sb.append(" and a.operdate > to_date('"+logQueryForm.getCzrqStart()+"','yyyy-mm-dd')");
}
if
(logQueryForm.getCzrqEnd()
!=
null
&&
!
""
.equals(logQueryForm.getCzrqEnd()))
{
sb.append(" and a.operdate <= to_date('"+logQueryForm.getCzrqEnd()+"','yyyy-mm-dd')");
}
if
(logQueryForm.getCzlx()
!=
null
&&
!
""
.equals(logQueryForm.getCzlx()))
{
sb.append(" and a.opertype = '"+logQueryForm.getCzlx()+"'");
}
if
(logQueryForm.getCzry()
!=
null
&&
!
""
.equals(logQueryForm.getCzry()))
{
sb.append(" and a.userid = '"+logQueryForm.getCzry()+"'");
}
sqlCount
+=
sb.toString();
sql
+=
sb.toString()
+
"
order by a.operdate desc) t1 where rownum<=
"
+
(pageIndex
+
1
)
*
pageSize
+
"
) t2 where t2.rid>
"
+
pageIndex
*
pageSize; //分页读取语句
//
System.out.println(sb.toString());
DBBean db
=
new
DBBean();
ResultSet rs
=
null
;
PreparedStatement prep
=
null
;
try
{
List resultList = db.getResultList(sql); //将ResultSet保存在List里返回
request.setAttribute("resultList",resultList); //把结果存入request
prep = db.getConnection().prepareStatement(sqlCount);
rs = prep.executeQuery();
if(rs.next()){
request.setAttribute("resultSize",new Integer(rs.getInt(1))); //将总记录数保存成Intger实例保存在request中
}
}
catch
(Exception ex)
{
ex.printStackTrace();
}
finally
{
if(db!=null){
db.closeConnection(); //关闭连接
}
}
StringBuffer sb
=
new
StringBuffer();
if
(logQueryForm.getCzrqStart()
!=
null
&&
!
""
.equals(logQueryForm.getCzrqStart()))
{ sb.append(" and a.operdate > to_date('"+logQueryForm.getCzrqStart()+"','yyyy-mm-dd')"); }
if
(logQueryForm.getCzrqEnd()
!=
null
&&
!
""
.equals(logQueryForm.getCzrqEnd()))
{ sb.append(" and a.operdate <= to_date('"+logQueryForm.getCzrqEnd()+"','yyyy-mm-dd')"); }
if
(logQueryForm.getCzlx()
!=
null
&&
!
""
.equals(logQueryForm.getCzlx()))
{ sb.append(" and a.opertype = '"+logQueryForm.getCzlx()+"'"); }
if
(logQueryForm.getCzry()
!=
null
&&
!
""
.equals(logQueryForm.getCzry()))
{ sb.append(" and a.userid = '"+logQueryForm.getCzry()+"'"); }
sqlCount
+=
sb.toString(); sql
+=
sb.toString()
+
"
order by a.operdate desc) t1 where rownum<=
"
+
(pageIndex
+
1
)
*
pageSize
+
"
) t2 where t2.rid>
"
+
pageIndex
*
pageSize; //分页读取语句
//
System.out.println(sb.toString());
DBBean db
=
new
DBBean(); ResultSet rs
=
null
; PreparedStatement prep
=
null
;
try
{ List resultList = db.getResultList(sql); //将ResultSet保存在List里返回 request.setAttribute("resultList",resultList); //把结果存入request prep = db.getConnection().prepareStatement(sqlCount); rs = prep.executeQuery(); if(rs.next()){
request.setAttribute("resultSize",new Integer(rs.getInt(1))); //将总记录数保存成Intger实例保存在request中 } }
catch
(Exception ex)
{ ex.printStackTrace(); }
finally
{ if(db!=null){ db.closeConnection(); //关闭连接 } }
其中的页面导航是英文的，只要修改org.displaytag.properties.TableTag.properties配置文件就可以把英文改成中文。同时还可以指定导出文件的类型以及文件名。
export.excel
=
trueexport.excel.label
=
<span class
=
"
export excel
"
>Excel </span>export.excel.include_header
=
trueexport.excel.filename
=
export.xls
如果不指定文件名，在点击导出excel的时候，就会在ie窗口中打开excel文件。很烦人！
指定文件名后就可以选择保存和打开了。
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