J2EE项目使用cewolf，ireport+jasperReport进行图表，报表的打印

一.用cewolf实现图表打印；（注意刷新问题）
    1.打印出柱状图；
       该程序主要为两个步骤：
         a.实现DatasetProducer接口；
         b.在cewolf标签中调用该匿名类，添好相关属性；
    以下为重要片断:
<%
    ArrayList list = null;
    Date[] dates=null;
   list = (ArrayList)session.getAttribute(SessionNames.OPERATION_STAT);
    PnrOperationLog operationLog = null;
    PnrOperationLog[] operationLogs = null;
for (int i=0;i<list.size();i++){
      operationLog = (PnrOperationLog)list.get(i);
      operationLogs[i] = operationLog;
      dates[i]=DateTimeFormatUtil.cnFormatToDate(operationLogs[i].getOperateDate());
%>
  <tr>
    <td align="center"><%=i+1%></td>
    <td align="center"><%=operationLog.getOperateDate()%></td>
    <td align="center"><%=operationLog.getOperateStat()%></td>
  </tr>
<%}
final ArrayList listN=list;
final PnrOperationLog[] operationLogsN=operationLogs;
final  Date[] datesN=dates;
if (pageContext.getAttribute("initFlag") == null) {
    DatasetProducer timeData = new DatasetProducer() {
        public Object produceDataset(Map params) {                    
        TimeSeries ts = new TimeSeries("Cewolf Release Schedule", Month.class);
        for (int i=0;i<listN.size();i++){                                    
            ts.add(new Month(datesN[i].getMonth(), datesN[i].getYear()), operationLogsN[i].getOperateStat());
             }
            return new TimeSeriesCollection(ts);
                }
        public String getProducerId() {
            return "TimeDataProducer";
        }
        public boolean hasExpired(Map params, Date since) {
            return false;//更据返回值false或true决定是否对其刷新；
        }
    };
    pageContext.setAttribute("timeData", timeData);
}
%>
</table>
<table border=0>
<TR>
<TD>
colorpaint<BR>
<cewolf:chart id="timeChart" title="TimeSeries" type="timeseries">
    <cewolf:colorpaint color="#EEEEFF"/>
    <cewolf:data>
        <cewolf:producer id="timeData"/>
    </cewolf:data>
</cewolf:chart>
<cewolf:img chartid="timeChart" renderer="cewolf" width="300" height="300"/>
</TD>
</TR>
</TABLE>
<%}         
   catch (Exception e) {
                 e.printStackTrace();
             }
%>
</body>
</html:html>  

<cewolf:chart id="timeChart" title="TimeSeries" type="timeseries">
    <cewolf:colorpaint color="#EEEEFF"/>
    <cewolf:data>
        <cewolf:producer id="timeData"/>
    </cewolf:data>
</cewolf:chart>
<cewolf:img chartid="timeChart" renderer="cewolf" width="300" height="300"/>
</TD>
</TR>
</TABLE>
<%}         
   catch (Exception e) {
                 e.printStackTrace();
             }
%>
</body>
</html:html>