不推荐用jsp, 用servlet 比较好,我这里有流程性的,你自己看着用吧,这东西用了2年,没发现问题。
通用的导出类,支持html,Excel,PDF三种

public class ReportType ...{

public static int HTML = 1;

public static int EXCEL = 2;

public static final int PDF = 3;


public static void export(HttpServletResponse response, JasperPrint jp, int type, String filename) throws Exception ...{
JRExporter exporter = null;

if (type == HTML) ...{
exporter = new JRHtmlExporter();
exporter.setParameter(JRHtmlExporterParameter.IS_USING_IMAGES_TO_ALIGN, false);
exporter.setParameter(JRHtmlExporterParameter.BETWEEN_PAGES_HTML, "");
// exporter.setParameter(JRHtmlExporterParameter.IS_REMOVE_EMPTY_SPACE_BETWEEN_ROWS, Boolean.TRUE);

} else if (type == EXCEL) ...{
exporter = new JRXlsExporter();
response.setContentType("application/vnd.ms-excel");
response.addHeader("Content-Disposition", new String(("attachment; filename=" + filename + ".xls").getBytes("GBK"), "ISO-8859-1"));
exporter.setParameter(JRXlsExporterParameter.IS_ONE_PAGE_PER_SHEET, Boolean.FALSE);
// exporter.setParameter(JRXlsExporterParameter.IS_REMOVE_EMPTY_SPACE_BETWEEN_ROWS, Boolean.TRUE);

} else if (type == PDF) ...{
exporter = new JRPdfExporter();
response.setContentType("application/pdf");
response.addHeader("Content-Disposition", new String(("attachment; filename=" + filename + ".pdf").getBytes("GBK"), "ISO-8859-1"));

} else ...{
return;
}
exporter.setParameter(JRExporterParameter.CHARACTER_ENCODING, "GBK");
exporter.setParameter(JRExporterParameter.JASPER_PRINT, jp);
exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, response.getOutputStream());
exporter.exportReport();
}
}
使用方法
String jasper = "jasper/saler/salerMonthSummary.jasper"; // 你的jasper文件地址
String filename = "营销中心业务员" + from + "-" + to + "销售汇总"; // 对于excel等需要下载的文件名

// 各种参数设置好
Map map = new HashMap();
map.put("YearFrom", from.getYear());
map.put("MonthFrom", from.getMonth());
map.put("YearTo", to.getYear());
map.put("MonthTo", to.getMonth());


// 读取jasper
JasperReport jr = (JasperReport) JRLoader.loadObjectFromLocation(jasper);

// 填充数据
JasperPrint jp = JasperFillManager.fillReport(jr, map, null);

// 判断是否正常
List<JRPrintPage> pages = jp.getPages();

if (pages.size() == 0) ...{
// 没有数据
return;
}

ReportType.export(response, jp, ReportType.EXCEL, filename);