http://shirlly.javaeye.com/blog/219511

struts.xml 下的配置
<result name="exportData" type="stream">
<!-- 指定下载文件的文件类型 -->
<param name="contentType">xls</param>
<!-- 指定下载文件的文件位置 -->
<param name="inputName">targetFile</param>
<param name="contentDisposition">attachment;filename="CarInsModification.xls"</param>
<!-- 指定下载文件的缓冲大小 -->
<param name="bufferSize">2048</param>
</result>


JSP页面代码
Java代码
<input type="button" class="button" value="导出EXCEL" onClick="onExport()" onMouseOver="switchClass(this)" onMouseOut="switchClass(this)">  
/导出全部记录  
        function onExport(){    
            var form=document.getElementById("searchForm");   
               form.action="carinsapply/CarInsModificationAction!exportModification.action";  
               //alert(getForm().action);  
               form.submit();   
        } 

<input type="button" class="button" value="导出EXCEL" onClick="onExport()" onMouseOver="switchClass(this)" onMouseOut="switchClass(this)">
//导出全部记录
        function onExport(){ 
        var form=document.getElementById("searchForm");
                form.action="carinsapply/CarInsModificationAction!exportModification.action";
                //alert(getForm().action);
                form.submit();
        }

Action层代码
Java代码
public String exportModification() throws FacadeException{  
        return Constants.Dispatcher.EXPORT_DATA;   
    }  
    /*  
    下载用的Action应该返回一个InputStream实例，  
    该方法对应在result里的inputName属性值为targetFile  
    */   
    public InputStream getTargetFile() throws Exception   
    {   
        filePath = "/exportdata";  
         filePath = "/exportdata";  
            try{  
                String fileName = carInsModificationFacade.exportModification(filePath);   
                if (!StringUtils.isBlank(fileName)){  
                    filePath = filePath + "/" + fileName;  
                    filePath = filePath.substring(1);//因为jsp页面中要加入<%= basePath%>所以要去掉前面的那个“/”  
                }else{  
                    filePath = null;  
                }  
            }catch(Exception fe){  
                fe.printStackTrace();  
                throw new FacadeException("导出批单数据出错!"+fe.getMessage());  
            }  
        return ServletActionContext.getServletContext().getResourceAsStream(filePath);   
    }  

public String exportModification() throws FacadeException{
return Constants.Dispatcher.EXPORT_DATA;
}
/*
下载用的Action应该返回一个InputStream实例，
该方法对应在result里的inputName属性值为targetFile
*/
public InputStream getTargetFile() throws Exception
{
filePath = "/exportdata";
filePath = "/exportdata";
try{
String fileName = carInsModificationFacade.exportModification(filePath);
if (!StringUtils.isBlank(fileName)){
filePath = filePath + "/" + fileName;
filePath = filePath.substring(1);//因为jsp页面中要加入<%= basePath%>所以要去掉前面的那个“/”
}else{
filePath = null;
}
}catch(Exception fe){
fe.printStackTrace();
throw new FacadeException("导出批单数据出错!"+fe.getMessage());
}
    return ServletActionContext.getServletContext().getResourceAsStream(filePath);
}

Facade层代码
Java代码
public String exportModification(String filePath) throws FacadeException{  
            String fileName = "carInsModification.xls";  
            try{  
                List<CarInsModificationInfo> modificationList = carInsModificationDAO.findAllModification();  
                if (modificationList.size() > 0){    
                    //开始创建excel文件     
                    filePath = ServletActionContext.getServletContext().getRealPath(filePath);   
                    filePath = filePath + "\\" + fileName;  
                    log.info("filepath="+filePath);  
                    WritableWorkbook book = Workbook.createWorkbook(new File(filePath));  //注意new File只能读取本地的路径    
                    WritableSheet sheet = book.createSheet("Sheet_1", 0);  
                    //先生成字段名   
                    //注意第一个是行，第二个是列   
                    sheet.addCell(new Label(0,0,"投保单号"));     
                    sheet.addCell(new Label(1,0,"批单号"));     
                    sheet.addCell(new Label(2,0,"批单状态"));   
                    sheet.addCell(new Label(3,0,"批改类型"));   
                    sheet.addCell(new Label(4,0,"保费变化"));    
                    sheet.addCell(new Label(5,0,"批改时间"));    
                    //开始读取数据  
                    for (int i=0;i<modificationList.size();i++){  
                        String policyCode = modificationList.get(i).getPolicyCode();  
                        if (!StringUtils.isBlank(policyCode)){   
                            sheet.addCell(new Label(0,i+1,policyCode));  
                        }  
                        String modiCode = modificationList.get(i).getModificationCode();  
                        if (!StringUtils.isBlank(modiCode)){   
                            sheet.addCell(new Label(1,i+1,modiCode));  
                        }   
                        String modiStateCode = modificationList.get(i).getMstateCode();   
                        if (!StringUtils.isBlank(modiStateCode)){  
                            String modiState = carInsModificationDAO.findNoteByCode("CpolicyState", modiStateCode);  
                            if (modiState == null){  
                                sheet.addCell(new Label(2,i+1,modiStateCode));  
                            }else{  
                                StringBuffer  modiStateBuf = new StringBuffer();  
                                modiStateBuf.append("(");  
                                modiStateBuf.append(modiStateCode);  
                                modiStateBuf.append(")");  
                                modiStateBuf.append(modiState);  
                                sheet.addCell(new Label(2,i+1,modiStateBuf.toString()));  
                            }  
                        }  
                        String modiTypeCode = modificationList.get(i).getCmodiType().getCode();  
                        if (!StringUtils.isBlank(modiTypeCode)){  
                            String modiType = carInsModificationDAO.findNoteByCode("CmodiType", modiTypeCode);  
                            if (modiType == null){  
                                sheet.addCell(new Label(3,i+1,modiTypeCode));  
                            }else{  
                                StringBuffer modiTypeBuf = new StringBuffer();  
                                modiTypeBuf.append("(");  
                                modiTypeBuf.append(modiTypeCode);  
                                modiTypeBuf.append(")");  
                                modiTypeBuf.append(modiType);  
                                sheet.addCell(new Label(3,i+1,modiTypeBuf.toString()));  
                            }  
                        }   
                        Double insChange = modificationList.get(i).getInsChange();   
                        if (insChange != null){  
                            sheet.addCell(new jxl.write.Number(4,i+1,insChange));  
                        }  
                        String modifyTime = DateFormatUtil.transferDateToString10(modificationList.get(i).getModifyTime());  
                        if (!StringUtils.isBlank(modifyTime)){  
                            sheet.addCell(new Label(5,i+1,modifyTime));  
                        }  
                    }  
                    book.write();        
                    book.close();  
                }else{  
                    fileName = "";  
                    throw new FacadeException("该批单信息不存在！");  
                }  
            }catch (Exception e){  
                throw new FacadeException("生成excel数据失败"+e);  
            }    
            return fileName;  
        }